Accordingly, mere appearance is not a safe
criterion
of the
identity of twins.
identity of twins.
Applied Eugenics by Roswell H. Johnson and Paul Popenoe
D.
, 242
Music, 96
Mutation, 441
Mutilations, 38
Myopia, 13, 59
McDonald, A. , 286
N
Nam Family, 143, 168
Naples, 303
Napoleon, 18, 179, 321
Nashville, Tenn. , 261
Nasmyth, G. , 322
National army, 319
National association for the advancement of colored people, 294, 295
National committee for mental hygiene, 172
Native whites, 238
Natural inheritance, 152
Natural selection, 148
Nature, 1
Nearing, S. , 261
Nebraska, 208
Negroes, 238, 280
Negro women, 387
Nevada, 187, 192, 296
New England, 260, 265, 274, 291, 358, 426
New Hampshire, 208
New Haven, Conn. , 261
New Jersey, 179, 193, 202
New Mexico, 187
Newport News, Va. , 288
Newsholme A. , 140, 141
New York, 11, 77, 172, 182, 186, 193, 233, 282, 286
New world, 324
Nice, 45, 47
Nicolin, 45
Night-blindness, 109, 433
Nilsson-Ehle, H. , 104
Nobility, 118
Nordic, 426
Nordic race, 280, 301, 357
Normal curve, 441
Normal school girls, 262
Norman conquest, 338
Normandy, 338
North Carolina, 326
North Dakota, 193
North European, 426
North Italians, 427
Northern United States, 326
Norway, 137
Norwich, Conn. , 192
Novikov, J. , 322
Nucleus, 441
Nurture, 1
O
Oberlin college, 244
Occupation, diseases of, 62
Odin, A. , 258
Ohio, 172
Ohio State University, 244
Oklahoma, 202, 208
Oliver, T. , 62
Oregon, 208
Organization of industry, 307
Oriental immigration, 313
Origin of eugenics, 147
Orthodactyly, 101, 102, 384, 433
Ovarian transplantation, 419
Ovize, 44
P
Pacific, 358
Paget parish, Bermuda, 205
Paine, J. H. , Figs. 16, 21
Paraguay, 325
Parents of great men, 423
Paris, 140, 155
Parker, G. , 233
Parole, 209
Partial segregation, 250
Past performance, 342
Passing of the great race, 426
Pasteur, L. , 333, 334
Patent, definition of, 441
Paternity, 219
Paul, C. , 63
Paupers, 157, 302
Pearl, R. , 47, 48, 99, 423
Pearson, K. , 10, 12, 55, 56, 57, 60, 85, 93, 99, 118, 119, 120,
121, 122, 124, 125, 126, 127, 134, 143, 144, 153, 212, 215,
224, 227, 231, 232, 344, 348, 349, 368, 404, 408, 409, 411,
413, 428, 433
Pedagogical celibacy, 390
Peerage, 232
Pennsylvania, 167, 187, 202, 208
Pennsylvania Dutch, 424
Pennsylvania, feeble-minded citizens of, 168
Pennsylvania, University of, 132
Penrose, C. A. , 203
Perrin, 372
Percy, H. , Fig. 19
Perry, S. J. , 124
Persians, 321
Perversion, 248
Pessimism, 247
Peters, I. L. , 226
Phi Beta Kappa, 241, 262
Philanthropy, 33
Philippine islands, 313
Philippines, 324
Phillips, B. A. , 287
Phillips, J. C. , 245, 267, 419
Phthisis, 126
Physical care of the infant, 278
Physical culture, 219
Physico-chemical effects, 38
Piang, Datto, 314
Piebaldism, 103, 433, Fig. 20
Pike, F. H. , 3
Pikipitanges, 132
Pilgrim fathers, 424
Piney folk, 168
Pitcairn islanders, 300
Pittsburgh, 138
Pittsburgh, University of, 234
Pituitary gland, 103
Plato, 150
Ploetz, A. , 118, 119, 408, 409, 410
Plymouth, England, 118
Poisons, racial, 48, 61, 63, Fig. 7
Poles, 259, 299, 427
Polygamy, 387
Polynesians, 127, 129
Pope, E. G. , 124
Popenoe, C. H. , 78
Popenoe, P. , vi, 244, 245, 270, 402, 423
Population, Malthusian, 151
Portland, Ore. , 261
Portuguese, 299, 302
Possible improvement of the human breed, etc. , 152
Poulton, E. B. , 43
Powys, A. O. , 272, 346
Pragmatic school, 352
Preferential mating, 214
Pre-natal care, 70
Pre-natal culture, 70
Pre-natal influence, 64
Pre-natal life, 155
Princeton college, 249
Probability curve, 78, 80, 441
Proctor fellowship, 249
Production, 307
Professional classes, 232
Professor's families, 228
Progressive changes, 39
Prohibited degrees of marriage, 222
Prohibition, 389
Propaganda, eugenic, 195
Prophylaxis, 252
Prostitution, 251
Protestant Christianity, 274
Protoplasm, 442
Prussia, 121, 321
Pseudo-celibacy, 248
Psychiatry, 442
Psychopathic inferiority, 302
Ptolemies, 206
Public charities association, 168
Punishment, 192
Punitive purpose, 192
Puritan, 298
Pyle, W. H. , 287
Q
Quadruplets, Fig. I
Quaker families, 118, 144
Quakers, English, 411
R
Rabaud, E. , 73
Rabbits, 45
Race betterment conference, first, 1
Race suicide, 257
Racial poisons, 48, 61, 63, 338, Fig. 7
Radot, R. V. , 333
Rapists, 193
Recessive, 433, 442
Reconstruction period, 325
Redfield, C. L. , 40, 421, 422, 423
Refraction, 59
Regression, 112, 442
Reid, G. A. , 50, 125, 129
Religion and eugenics, 393
Remote ancestors, 338
Research fellowship, 153
Reserve, 251
Restriction, methods of, 184
Restrictive eugenics, 175, 184
Retrogression, 42
Revolutionary war, 426
Reward and punishment, 395
Rhode Island, 261
Rice, J. M. , 95
Richmond, Va. , 288
Riis, J. , 1
Roman catholic church, 273
Roman republic, 284
Rome custodial asylum, 186
Roosevelt, T. , 308
Ross, E. A. , X, 301
Roumanians, 299, 311, 427
Round-headed type, 427
Rousseau, J. J. , 75
Royal families, 17, 20, 118, 410
Rubin, von Gruber and, 204
Ruskin, 342
Russell Sage Foundation, 186
Russia, 137, 302, 325
Russian Jews, 427
Russians, 259, 302, 311, 427
Russo-Hebrew, 302
Russo-Japanese war, 321
Ruthenians, 311
S
Sacerdotal celibacy, 222
St. Louis, 154
St. Paul, public schools of, 372
Salpingectomy, 185
San Domingo, 289
Save the babies propaganda, 273, 412
Saxon, 426
Scandinavia, 299
Scandinavian, 311
Schonberg, Berlin, 382
School acquaintance, 234
Schuster, E. , 93, 153, 435
Scope of eugenics, 152
Scotch, 259, 311
Scotland, 237
Scrub, 229
Seashore, C. E. , 343
Segregation, 88, 185, 430, 442
Selection, 442
Selection, natural, 148
Selective conscription, 320
Self-repression, 251
Sewall, S. E. , 153
Sex determination, 347
Sex equality, 379
Sex ethics, 252
Sex histories, 252
Sex hygiene movement, 385
Sex hygienists, 154
Sex-limited, 442
Sex-linked, 442
Sex-linked characters, 433
Sexual perverts, 193
Sexual selection, 136, 215, 262, 325, 442
Sexual variety, 247
Shepherd's purse, 104
Shinn, M. W. , 243
Short-fingerness, 102
Shorthorn cattle, 423
Short-sightedness, 12
Shull, G. H. , 104
Sibs, 202
Sidis, B. , 86
Simpson, Q. V. , Fig. 20
Single tax, 353
Sing Sing, 182
Sixty family, 168
Slavs, 299, 304
Smith's island, 206
Smith, M. R. , 241, 265
Snow, E. C. , 121, 413
Social status, 229
Socialism, 362
Solvay Institut, 155
Soma, 443
Somerset parish, Bermuda, 205
South Atlantic, 358
South Carolina, 187
South Dakota, 208, 296
South Italians, 427
South Slavs, 302
Southern United States, 291, 325
Southwestern state normal school, 217
Spain, 19, 137
Spanish, 324
Spanish conquest, 131
Spanish wells, 203
Spartans, 171
Spencer, H. , 33, 34, 35, 41, 136, 165, 348
Spermatozoa, 45
Spirochaete, 62
Sprague, R. J. , 240, 253, 255, 262
Standards of education, 275
Stanford University, 245
Starch, D. , 21
State Board of Charities of New York, 435
Station for Experimental Evolution, 100
Sterilization, 185
Stetson, G. R. , 286
Stevenson, R. L. , 131, 301
Stiles, C. W. , 291
Stockard, C. R. , 44, 45, 47
Strong, A. C. , 287
Stuart line, 19
Sturge, M. D. , 55
Sturtevant, A. H. , 101
Subordination of women, 362
Substitution tests, 288
Superficial characteristics, 227
Superior, marriage rate of, 237
Superiority of eldest, 344
Sweden, 138, 155
Swedes, 259
Switzerland, 56, 138, 155
Symphalangism, 433, Fig. 17
Syphilis, 63
Syphilitics, 193
Syracuse University, 245
Syrians, 299, 302
T
Taboo, 222, 297
Tail-male line, 331
Talent, hereditary, 151
Tarbell, I. M. , 333
Tasmania, 131, 132
Taxation, 352
Taylor, J. H. , Figs. 22, 25
Telegony, 73
Ten commandments, 394
Tennessee, 187
Terman, L. M. , 106
Teutonic, 426
Teutonic nations, 52
Texas, 202
Theism, 398
Theistic religion, 395
Theognis of Megara, 150
Therapeutic, 192
Thirty Years' war, 326
Thompson, J. A. , 29, 34, 435
Thorndike, E. L. , 10, 11, 21, 76, 79, 90, 91, 373
Threadworn, 7
Tobacco, 45, 63
Todde, C. , 45
Trades unionism, 388
Training school of Vineland, N. J. , 188
Trait, 443
Transmissibility, 38
Tropical fevers, 133
Tropics, 35
Truro, 206
Tuberculosis, 57, 124, 199, 302
Turkey, 137
Turkish, 311
Turner, J. M. W. , 68, 342
Turpitude, moral, 194
Twins, 90, Figs. 24, 25
U
Unfitness, 121
Unit-character, 443
United States, 16, 24, 137, 155, 289, 291, 407
U. S. public health service, 303
University of London, 153
University of Pittsburgh, 216
Unlike, marriage of, 212
Uruguay, 325
Use and disuse, 38
Useful works of reference, 435
Utah, 187, 208
Uterine infection, 38
V
Vagrants, 302
Variation, 443
Variate difference correlation, 121
Vasectomy, 184
Vassar College, 240
Vedder, E. B. , 387
Veblen, T. , 228
Venereal diseases, 248, 251
Venereal infection, 386
Vermont, 326
Vestigial, 443
Victor Emmanuel, 19
Villard, O. G. , 294
Vineland, N. J. , 71
Vineyard, Martha's, 154
Virginia, 326
Vision, 59
Vocational guidance, 371
Vocational training, 371
Voisin, 206
Volta bureau, 154
W
Wales, 122, 138
Wallin, J. E. W. , 188
Walter, H. E. , 435
War, 318
Warne, F. J. , 304
Washington, 192, 208
Washington, D. C. , 154, 233, 261, 286
Washington, G. , 337
Washington Seminary, 242
Weakness, matings involving, 200
Webb, S. , 269
Wedgewood, E. , 208
Weismann, A. , 25, 26, 44, 431
Weldon, W. F. R. , 99, 118
Wellesley College, 235, 239, 242, 262, 263
Wellesley scholarships, 262
Welsh, 259, 311
West, B. , 342
West, J. , 132
West north central states, 358
West south central states, 358
West Virginia, 187
Westergaard, H. , 57
Wheat, 104
Whetham, W. C. D. , 435, 436
White slavery, 193
Whitman, C. O. , 348
Who's Who, 246
Willcox, W. F. , 269
Williams, W. , 303
William the Conqueror, 338
William of Occam, 93
William of Orange, 19
William the Silent, 19
Wilson, J. A. , 13
Wilson, W. , 310
Wisconsin, 172, 194
Wisconsin, University of, 45, 63, 244
Woman suffrage, 380
Woman's colleges, 383
Woods, A. W. , 334
Woods, E. B. , 372, 373
Woods, F. A. , 3, 17, 18, 19, 89, 144, 260, 327, 341, 373
Wright, L. E. , 314
Wright, S. , vi. , 433
Y
Yale College, 245, 265, 266
Yerkes, R. M. , 87, 88
Young Men's Christian Association, 155, 235, 336
Young Peoples Society of Christian Endeavor, 234
Young Women's Christian Association, 235
Yule, G. U. , 144
Z
Zero Family, 168
Zygote, 26, 443
Zymotic, 443
Zulus, 284
* * * * *
FOOTNOTES
[1] See Woods, Frederick Adams, "Laws of Diminishing Environmental
Influences," _Popular Science Monthly_, April, 1910, pp. 313-336;
Huxley, J. S. , _The Individual in the Animal Kingdom_, Cambridge and New
York, 1912. Pike, F. H. , and Scott, E. L. , "The Significance of Certain
Internal Conditions of the Organism in Organic Evolution," _American
Naturalist_, Vol. XLIX, pp. 321-359, June, 1915.
[2] There is one line of experiment which is simple and striking enough
to deserve mention--namely, ovarian transplantation. A description of
this is given in Appendix A.
[3] Galton, Francis, _Inquiries into Human Faculty_, 1907 edition, pp.
153-173. This volume of Galton's, which was first published in 1883, has
been reissued in Everyman's Library, and should be read by all
eugenists.
[4] What is said here refers to positive correlations, which are the
only kind involved in this problem. Correlations may also be negative,
lying between 0 and -1; for instance, if we measured the correlation
between a man's lack of appetite and the time that had elapsed since his
last meal, we would have to express it by a negative fraction, the minus
sign showing that the greater his satiety, the less would be the time
since his repast. The best introduction to correlations is Elderton's
_Primer of Statistics_ (London, 1912).
[5] Dr. Thorndike's careful measurements showed that it is impossible to
draw a hard and fast line between identical twins and ordinary twins.
There is no question as to the existence of the two kinds, but the
ordinary twins may happen to be so nearly alike as to resemble identical
twins.
Accordingly, mere appearance is not a safe criterion of the
identity of twins. His researches were published in the _Archives of
Philosophy, Psychology and Scientific Methods_, No. 1, New York, 1905.
[6] _A First Study of the Inheritance of Vision and the Relative
Influence of Heredity and Environment on Sight. _ By Amy Barrington and
Karl Pearson. Eugenics Laboratory (London), Memoir Series V.
[7] Dr. James Alexander Wilson, assistant surgeon of the Opthalmic
Institute, Glasgow, published an analysis of 1,500 cases of myopia in
the _British Medical Journal_, p. 395, August 29, 1914. His methods are
not above criticism, and too much importance should not be attached to
his results, which show that in 58% of the cases heredity can be
credited with the myopia of the patient. In 12% of the cases it was due
to inflammation of the cornea (keratitis) while in the remaining 30% no
hereditary influence could be proved, but various reasons made him feel
certain that in many cases it existed. The distribution of myopia by
trades and professions among his patients is suggestive: 65% of the
cases among school children showed myopic heredity; 63% among housewives
and domestic servants; 68% among shop and factory works; 60% among
clerks and typists; 60% among laborers and miners. If environment really
played an active part, one would not expect to find this similarity in
percentages between laborers and clerks, between housewives and
schoolteachers, etc.
[8] _The Influence of Unfavourable Home Environment and Defective
Physique on the Intelligence of School Children. _ By David Heron.
Eugenics Laboratory (London), Memoir Series No. VIII.
[9] _Hereditary Genius; an Inquiry into its Laws and Consequences. _
London, 1869.
[10] Woods, Frederick Adams, "Heredity and the Hall of Fame," _Popular
Science Monthly_, May, 1913.
[11] Woods, Frederick Adams, _Mental and Moral Heredity in Royalty_, New
York, 1906. See also "Sovereigns and the Supposed Influence of
Opportunity," _Science_, n. s. , XXXIX, No. 1016, pp. 902-905, June 19,
1914, where Dr. Woods answers some criticisms of his work.
[12] _Educational Psychology_, Vol. III, p. 306. Starch's results are
also quoted from Thorndike.
[13] Jean Baptiste Lamarck, a French naturalist, born in 1744, was one
of the pioneers in the philosophical study of evolution. The theory
(published in 1809) for which he is best known is as follows: "Changes
in the animal's surroundings are responded to by changes in its habits. "
"Any particular habit involves the regular use of some organs and the
disuse of others. Those organs which are used will be developed and
strengthened, those not used diminished and weakened, and the changes so
produced will be transmitted to the offspring, and thus progressive
development of particular organs will go on from generation to
generation. " His classical example is the neck of the giraffe, which he
supposes to be long because, for generation after generation, the
animals stretched their necks in order to get the highest leaves from
the trees.
[14] Boas, F. , _Changes in Body Form of Descendants of Immigrants_,
1911.
[15] _Civilization and Climate. _ By Ellsworth Huntington, Yale
University Press, 1916.
[16] _American Naturalist_, L. , pp. 65-89, 144-178, Feb. and Mar. , 1916.
[17] _Proc. Am. Philos. Soc. _ LV, pp. 243-259, 1916.
[18] Dr. Reid is the author who has most effectively called attention to
this relation between alcohol and natural selection. Those interested
will find a full treatment in his books, _The Present Evolution of Man_,
_The Laws of Heredity_, and _The Principles of Heredity_.
[19] _Principles of Psychology_, ii, p. 543.
[20] Leon J. Cole points out that this may be due in considerable part
to less voluntary restriction of offspring on the part of those who are
often under the influence of alcohol.
[21] For a review of the statistical problems involved, see Karl
Pearson. An attempt to correct some of the misstatements made by Sir
Victor Horsley, F. R. S. , F. R. C. S. , and Mary D. Sturge, M. D. , in
their criticisms of the Galton Laboratory Memoir: _First Study of the
Influence of Parental Alcoholism_, etc. ; and Professor Pearson's various
popular lectures, also _A Second Study of the Influence of Parental
Alcoholism on the Physique and Intelligence of Offspring_. By Karl
Pearson and Ethel M. Elderton. Eugenics Laboratory Memoir Series XIII.
[22] _A First Study of the Influence of Parental Alcoholism on the
Physique and Intelligence of Offspring. _ By Ethel M. Elderton and Karl
Pearson. Eugenics Laboratory Memoir Series X. Harald Westergaard, who
reexamined the Elderton-Pearson data, concludes that considerable
importance is to be attached to the selective action of alcohol, the
weaklings in the alcoholic families having been weeded out early in
life.
[23] Prohibition would have some _indirect_ eugenic effects, which will
be discussed in Chapter XVIII.
[24] Chapter XXX, verses 31-43. A knowledge of the pedigree of Laban's
cattle would undoubtedly explain where the stripes came from. It is
interesting to note how this idea persists: a correspondent has recently
sent an account of seven striped lambs born after their mothers had seen
a striped skunk. The actual explanation is doubtless that suggested by
Heller in the _Journal of Heredity_, VI, 480 (October, 1915), that a
stripe is part of the ancestral coat pattern of the sheep, and appears
from time to time because of reversion.
[25] Such a skin affection, known as icthyosis, xerosis or xeroderma, is
usually due to heredity. Davenport says it "is especially apt to be
found in families in which consanguineous marriages occur and this fact,
together with the pedigrees [which he studied], suggests that it is due
to the absence of some factor that controls the process of cornification
of the skin. On this hypothesis a normal person who belongs to an
affected family may marry into a normal family with impunity, but cousin
marriages are to be avoided. " See Davenport, C. B. , _Heredity in
Relation to Eugenics_, p. 134. New York, 1911.
[26] Its eugenics is to be effected through the mental exertion of
mothers. And we have lately been in correspondence with a western
attorney who is endeavoring to form an association of persons who will
agree to be the parents of "willed" children. By this means, he has
calculated (and sends a chart to prove it) that it will require only
four generations to produce the Superman.
[27] _Life and Letters of Charles Darwin_, Vol. I, p. 302, New York,
1897. The letter is dated 1844.
[28] Goddard, H. H. , _Feeble-mindedness_, p. 359. New York, the
Macmillan Company, 1914.
[29] For a review of the evidence consult an article on "Telegony" by
Dr. Etienne Rabaud in the _Journal of Heredity_, Vol. V, No. 9, pp.
389-400; September, 1914.
[30] It will be recalled that the coefficient of correlation measures
the resemblance between two variables on a scale between 0 and-1 or +1.
If the correlation is zero, there is no constant relation; if it is
unity, any change in one must result in a determinate change in the
other; if it is 0. 5, it means that when one of the variables deviates
from the mean of its class by a given amount, the other variable will
deviate from the mean of its class by 50% of that amount (each deviation
being measured in terms of the variability of its own class, in order
that they may be properly comparable. )
[31] Sidis, Boris, M. A. , Ph. D. , M. D. , "Neurosis and Eugenics," _Medical
Review of_ _Reviews_, Vol. XXI, No. 10, pp. 587-594, New York, October,
1915. A psychologist who writes of "some miraculous germ-plasm
(chromatin) with wonderful dominant 'units' (Chromosomes)" is hardly a
competent critic of the facts of heredity.
[32] In a letter to the _Journal of Heredity_, under date of August 4,
1916.
[33] Galton, Francis, _Inquiries into Human Faculty_, p. 167, London,
1907.
[34] Woods, Frederick Adams, _Heredity in Royalty_, New York, 1906.
[35] _Op. cit. _, pp. 170-171.
[36] Thorndike, E. L. , "Measurements of Twins," _Arch. of Philos. ,
Psych. and Sci. Methods_, No. 1, New York, 1905; summarized in his
_Educational Psychology_, Vol. III, pp. 247-251, New York, 1914.
Measured on a scale where 1 = identity, he found that twins showed a
resemblance to each other of about . 75, while ordinary brothers of about
the same age resembled each other to the extent of about . 50 only. The
resemblance was approximately the same in both physical and mental
traits.
[37] The quotations in this and the following paragraph are from
_Thorndike's Educational Psychology_, pp. 304-305, Vol. III.
[38] _Biometrika_, Vol. III, p. 156.
[39] "William of Occam's Razor" is the canon of logic which declares
that it is unwise to seek for several causes of an effect, if a single
cause is adequate to account for it.
[40] Schuster, Edgar, _Eugenics_, pp. 150-163, London, 1913.
[41] _Educational Psychology_ (1914), Vol. III, p. 235.
[42] Cobb, Margaret V. , _Journal of Educational Psychology_, viii, pp.
1-20, Jan. , 1917.
[43] This is not true of the small English school of biometrists,
founded by Sir Francis Galton, W. F. R. Weldon and Karl Pearson, and now
led by the latter. It has throughout denied or minified Mendelian
results, and depended on the treatment of inheritance by a study of
correlations. With the progress of Mendelian research, biometric methods
must be supplemented with pedigree studies. In human heredity, on the
other hand, because of the great difficulties attendant upon an
application of Mendelian methods, the biometric mode of attack is still
the most useful, and has been largely used in the present book. It has
been often supposed that the methods of the two schools (biometry and
Mendelism) are antagonistic. They are rather supplementary, each being
valuable in cases where the other is less applicable. See Pearl,
Raymond, _Modes of Research in Genetics_, p. 182, New York, 1915
[44] Few people realize what large numbers of plants and animals have
been bred for experimental purposes during the last decade; W. E. Castle
of Bussey Institution, Forest Hills, Mass. , has bred not less than
45,000 rats. In the study of a single character, the endosperm of maize,
nearly 100,000 pedigreed seeds have been examined by different students.
Workers at the University of California have tabulated more than 10,000
measurements on flower size alone, in tobacco hybrids. T. H. Morgan and
his associates at Columbia University have bred and studied more than
half a million fruit flies, and J. Arthur Harris has handled more than
600,000 bean-plants at the Carnegie Institution's Station for
Experimental Evolution, Cold Spring Harbor, L. I. While facts of human
heredity, and of inheritance in large mammals generally, are often
grounded on scanty evidence, it must not be thought that the fundamental
generalizations of heredity are based on insufficient data.
[45] For a brief account of Mendelism, see Appendix D.
[46] Of course these factors are not of equal importance; some of them
produce large changes and some, as far as can be told, are of minor
significance. The factors, moreover, undergo large changes from time to
time, thus producing mutations; and it is probable small changes as
well, the evidence for which requires greater refinements of method than
is usual among those using the pedigree method.
[47] _A Critique of the Theory of Evolution_, by Thomas Hunt Morgan,
professor of experimental zoology in Columbia University. Princeton
University Press, 1916. This book gives the best popular account of the
studies of heredity in Drosophila. The advanced student will find _The
Mechanism of Mendelian Heredity_ (New York, 1915), by Morgan,
Sturtevant, Muller, and Bridges, indispensable, but it is beyond the
comprehension of most beginners.
[48] "On the Inheritance of Some Characters in Wheat," A. and G. Howard,
_Mem. Dep. of Agr. India_, V: 1-46, 1912. This careful and important
work has never received the recognition it deserves, apparently because
few geneticists have seen it. While the multiple factors in wheat seem
to be different, those reported by East and Shull appear to be merely
duplicates.
[49] "The Nature of Mendelian Units. " By G. N.
Music, 96
Mutation, 441
Mutilations, 38
Myopia, 13, 59
McDonald, A. , 286
N
Nam Family, 143, 168
Naples, 303
Napoleon, 18, 179, 321
Nashville, Tenn. , 261
Nasmyth, G. , 322
National army, 319
National association for the advancement of colored people, 294, 295
National committee for mental hygiene, 172
Native whites, 238
Natural inheritance, 152
Natural selection, 148
Nature, 1
Nearing, S. , 261
Nebraska, 208
Negroes, 238, 280
Negro women, 387
Nevada, 187, 192, 296
New England, 260, 265, 274, 291, 358, 426
New Hampshire, 208
New Haven, Conn. , 261
New Jersey, 179, 193, 202
New Mexico, 187
Newport News, Va. , 288
Newsholme A. , 140, 141
New York, 11, 77, 172, 182, 186, 193, 233, 282, 286
New world, 324
Nice, 45, 47
Nicolin, 45
Night-blindness, 109, 433
Nilsson-Ehle, H. , 104
Nobility, 118
Nordic, 426
Nordic race, 280, 301, 357
Normal curve, 441
Normal school girls, 262
Norman conquest, 338
Normandy, 338
North Carolina, 326
North Dakota, 193
North European, 426
North Italians, 427
Northern United States, 326
Norway, 137
Norwich, Conn. , 192
Novikov, J. , 322
Nucleus, 441
Nurture, 1
O
Oberlin college, 244
Occupation, diseases of, 62
Odin, A. , 258
Ohio, 172
Ohio State University, 244
Oklahoma, 202, 208
Oliver, T. , 62
Oregon, 208
Organization of industry, 307
Oriental immigration, 313
Origin of eugenics, 147
Orthodactyly, 101, 102, 384, 433
Ovarian transplantation, 419
Ovize, 44
P
Pacific, 358
Paget parish, Bermuda, 205
Paine, J. H. , Figs. 16, 21
Paraguay, 325
Parents of great men, 423
Paris, 140, 155
Parker, G. , 233
Parole, 209
Partial segregation, 250
Past performance, 342
Passing of the great race, 426
Pasteur, L. , 333, 334
Patent, definition of, 441
Paternity, 219
Paul, C. , 63
Paupers, 157, 302
Pearl, R. , 47, 48, 99, 423
Pearson, K. , 10, 12, 55, 56, 57, 60, 85, 93, 99, 118, 119, 120,
121, 122, 124, 125, 126, 127, 134, 143, 144, 153, 212, 215,
224, 227, 231, 232, 344, 348, 349, 368, 404, 408, 409, 411,
413, 428, 433
Pedagogical celibacy, 390
Peerage, 232
Pennsylvania, 167, 187, 202, 208
Pennsylvania Dutch, 424
Pennsylvania, feeble-minded citizens of, 168
Pennsylvania, University of, 132
Penrose, C. A. , 203
Perrin, 372
Percy, H. , Fig. 19
Perry, S. J. , 124
Persians, 321
Perversion, 248
Pessimism, 247
Peters, I. L. , 226
Phi Beta Kappa, 241, 262
Philanthropy, 33
Philippine islands, 313
Philippines, 324
Phillips, B. A. , 287
Phillips, J. C. , 245, 267, 419
Phthisis, 126
Physical care of the infant, 278
Physical culture, 219
Physico-chemical effects, 38
Piang, Datto, 314
Piebaldism, 103, 433, Fig. 20
Pike, F. H. , 3
Pikipitanges, 132
Pilgrim fathers, 424
Piney folk, 168
Pitcairn islanders, 300
Pittsburgh, 138
Pittsburgh, University of, 234
Pituitary gland, 103
Plato, 150
Ploetz, A. , 118, 119, 408, 409, 410
Plymouth, England, 118
Poisons, racial, 48, 61, 63, Fig. 7
Poles, 259, 299, 427
Polygamy, 387
Polynesians, 127, 129
Pope, E. G. , 124
Popenoe, C. H. , 78
Popenoe, P. , vi, 244, 245, 270, 402, 423
Population, Malthusian, 151
Portland, Ore. , 261
Portuguese, 299, 302
Possible improvement of the human breed, etc. , 152
Poulton, E. B. , 43
Powys, A. O. , 272, 346
Pragmatic school, 352
Preferential mating, 214
Pre-natal care, 70
Pre-natal culture, 70
Pre-natal influence, 64
Pre-natal life, 155
Princeton college, 249
Probability curve, 78, 80, 441
Proctor fellowship, 249
Production, 307
Professional classes, 232
Professor's families, 228
Progressive changes, 39
Prohibited degrees of marriage, 222
Prohibition, 389
Propaganda, eugenic, 195
Prophylaxis, 252
Prostitution, 251
Protestant Christianity, 274
Protoplasm, 442
Prussia, 121, 321
Pseudo-celibacy, 248
Psychiatry, 442
Psychopathic inferiority, 302
Ptolemies, 206
Public charities association, 168
Punishment, 192
Punitive purpose, 192
Puritan, 298
Pyle, W. H. , 287
Q
Quadruplets, Fig. I
Quaker families, 118, 144
Quakers, English, 411
R
Rabaud, E. , 73
Rabbits, 45
Race betterment conference, first, 1
Race suicide, 257
Racial poisons, 48, 61, 63, 338, Fig. 7
Radot, R. V. , 333
Rapists, 193
Recessive, 433, 442
Reconstruction period, 325
Redfield, C. L. , 40, 421, 422, 423
Refraction, 59
Regression, 112, 442
Reid, G. A. , 50, 125, 129
Religion and eugenics, 393
Remote ancestors, 338
Research fellowship, 153
Reserve, 251
Restriction, methods of, 184
Restrictive eugenics, 175, 184
Retrogression, 42
Revolutionary war, 426
Reward and punishment, 395
Rhode Island, 261
Rice, J. M. , 95
Richmond, Va. , 288
Riis, J. , 1
Roman catholic church, 273
Roman republic, 284
Rome custodial asylum, 186
Roosevelt, T. , 308
Ross, E. A. , X, 301
Roumanians, 299, 311, 427
Round-headed type, 427
Rousseau, J. J. , 75
Royal families, 17, 20, 118, 410
Rubin, von Gruber and, 204
Ruskin, 342
Russell Sage Foundation, 186
Russia, 137, 302, 325
Russian Jews, 427
Russians, 259, 302, 311, 427
Russo-Hebrew, 302
Russo-Japanese war, 321
Ruthenians, 311
S
Sacerdotal celibacy, 222
St. Louis, 154
St. Paul, public schools of, 372
Salpingectomy, 185
San Domingo, 289
Save the babies propaganda, 273, 412
Saxon, 426
Scandinavia, 299
Scandinavian, 311
Schonberg, Berlin, 382
School acquaintance, 234
Schuster, E. , 93, 153, 435
Scope of eugenics, 152
Scotch, 259, 311
Scotland, 237
Scrub, 229
Seashore, C. E. , 343
Segregation, 88, 185, 430, 442
Selection, 442
Selection, natural, 148
Selective conscription, 320
Self-repression, 251
Sewall, S. E. , 153
Sex determination, 347
Sex equality, 379
Sex ethics, 252
Sex histories, 252
Sex hygiene movement, 385
Sex hygienists, 154
Sex-limited, 442
Sex-linked, 442
Sex-linked characters, 433
Sexual perverts, 193
Sexual selection, 136, 215, 262, 325, 442
Sexual variety, 247
Shepherd's purse, 104
Shinn, M. W. , 243
Short-fingerness, 102
Shorthorn cattle, 423
Short-sightedness, 12
Shull, G. H. , 104
Sibs, 202
Sidis, B. , 86
Simpson, Q. V. , Fig. 20
Single tax, 353
Sing Sing, 182
Sixty family, 168
Slavs, 299, 304
Smith's island, 206
Smith, M. R. , 241, 265
Snow, E. C. , 121, 413
Social status, 229
Socialism, 362
Solvay Institut, 155
Soma, 443
Somerset parish, Bermuda, 205
South Atlantic, 358
South Carolina, 187
South Dakota, 208, 296
South Italians, 427
South Slavs, 302
Southern United States, 291, 325
Southwestern state normal school, 217
Spain, 19, 137
Spanish, 324
Spanish conquest, 131
Spanish wells, 203
Spartans, 171
Spencer, H. , 33, 34, 35, 41, 136, 165, 348
Spermatozoa, 45
Spirochaete, 62
Sprague, R. J. , 240, 253, 255, 262
Standards of education, 275
Stanford University, 245
Starch, D. , 21
State Board of Charities of New York, 435
Station for Experimental Evolution, 100
Sterilization, 185
Stetson, G. R. , 286
Stevenson, R. L. , 131, 301
Stiles, C. W. , 291
Stockard, C. R. , 44, 45, 47
Strong, A. C. , 287
Stuart line, 19
Sturge, M. D. , 55
Sturtevant, A. H. , 101
Subordination of women, 362
Substitution tests, 288
Superficial characteristics, 227
Superior, marriage rate of, 237
Superiority of eldest, 344
Sweden, 138, 155
Swedes, 259
Switzerland, 56, 138, 155
Symphalangism, 433, Fig. 17
Syphilis, 63
Syphilitics, 193
Syracuse University, 245
Syrians, 299, 302
T
Taboo, 222, 297
Tail-male line, 331
Talent, hereditary, 151
Tarbell, I. M. , 333
Tasmania, 131, 132
Taxation, 352
Taylor, J. H. , Figs. 22, 25
Telegony, 73
Ten commandments, 394
Tennessee, 187
Terman, L. M. , 106
Teutonic, 426
Teutonic nations, 52
Texas, 202
Theism, 398
Theistic religion, 395
Theognis of Megara, 150
Therapeutic, 192
Thirty Years' war, 326
Thompson, J. A. , 29, 34, 435
Thorndike, E. L. , 10, 11, 21, 76, 79, 90, 91, 373
Threadworn, 7
Tobacco, 45, 63
Todde, C. , 45
Trades unionism, 388
Training school of Vineland, N. J. , 188
Trait, 443
Transmissibility, 38
Tropical fevers, 133
Tropics, 35
Truro, 206
Tuberculosis, 57, 124, 199, 302
Turkey, 137
Turkish, 311
Turner, J. M. W. , 68, 342
Turpitude, moral, 194
Twins, 90, Figs. 24, 25
U
Unfitness, 121
Unit-character, 443
United States, 16, 24, 137, 155, 289, 291, 407
U. S. public health service, 303
University of London, 153
University of Pittsburgh, 216
Unlike, marriage of, 212
Uruguay, 325
Use and disuse, 38
Useful works of reference, 435
Utah, 187, 208
Uterine infection, 38
V
Vagrants, 302
Variation, 443
Variate difference correlation, 121
Vasectomy, 184
Vassar College, 240
Vedder, E. B. , 387
Veblen, T. , 228
Venereal diseases, 248, 251
Venereal infection, 386
Vermont, 326
Vestigial, 443
Victor Emmanuel, 19
Villard, O. G. , 294
Vineland, N. J. , 71
Vineyard, Martha's, 154
Virginia, 326
Vision, 59
Vocational guidance, 371
Vocational training, 371
Voisin, 206
Volta bureau, 154
W
Wales, 122, 138
Wallin, J. E. W. , 188
Walter, H. E. , 435
War, 318
Warne, F. J. , 304
Washington, 192, 208
Washington, D. C. , 154, 233, 261, 286
Washington, G. , 337
Washington Seminary, 242
Weakness, matings involving, 200
Webb, S. , 269
Wedgewood, E. , 208
Weismann, A. , 25, 26, 44, 431
Weldon, W. F. R. , 99, 118
Wellesley College, 235, 239, 242, 262, 263
Wellesley scholarships, 262
Welsh, 259, 311
West, B. , 342
West, J. , 132
West north central states, 358
West south central states, 358
West Virginia, 187
Westergaard, H. , 57
Wheat, 104
Whetham, W. C. D. , 435, 436
White slavery, 193
Whitman, C. O. , 348
Who's Who, 246
Willcox, W. F. , 269
Williams, W. , 303
William the Conqueror, 338
William of Occam, 93
William of Orange, 19
William the Silent, 19
Wilson, J. A. , 13
Wilson, W. , 310
Wisconsin, 172, 194
Wisconsin, University of, 45, 63, 244
Woman suffrage, 380
Woman's colleges, 383
Woods, A. W. , 334
Woods, E. B. , 372, 373
Woods, F. A. , 3, 17, 18, 19, 89, 144, 260, 327, 341, 373
Wright, L. E. , 314
Wright, S. , vi. , 433
Y
Yale College, 245, 265, 266
Yerkes, R. M. , 87, 88
Young Men's Christian Association, 155, 235, 336
Young Peoples Society of Christian Endeavor, 234
Young Women's Christian Association, 235
Yule, G. U. , 144
Z
Zero Family, 168
Zygote, 26, 443
Zymotic, 443
Zulus, 284
* * * * *
FOOTNOTES
[1] See Woods, Frederick Adams, "Laws of Diminishing Environmental
Influences," _Popular Science Monthly_, April, 1910, pp. 313-336;
Huxley, J. S. , _The Individual in the Animal Kingdom_, Cambridge and New
York, 1912. Pike, F. H. , and Scott, E. L. , "The Significance of Certain
Internal Conditions of the Organism in Organic Evolution," _American
Naturalist_, Vol. XLIX, pp. 321-359, June, 1915.
[2] There is one line of experiment which is simple and striking enough
to deserve mention--namely, ovarian transplantation. A description of
this is given in Appendix A.
[3] Galton, Francis, _Inquiries into Human Faculty_, 1907 edition, pp.
153-173. This volume of Galton's, which was first published in 1883, has
been reissued in Everyman's Library, and should be read by all
eugenists.
[4] What is said here refers to positive correlations, which are the
only kind involved in this problem. Correlations may also be negative,
lying between 0 and -1; for instance, if we measured the correlation
between a man's lack of appetite and the time that had elapsed since his
last meal, we would have to express it by a negative fraction, the minus
sign showing that the greater his satiety, the less would be the time
since his repast. The best introduction to correlations is Elderton's
_Primer of Statistics_ (London, 1912).
[5] Dr. Thorndike's careful measurements showed that it is impossible to
draw a hard and fast line between identical twins and ordinary twins.
There is no question as to the existence of the two kinds, but the
ordinary twins may happen to be so nearly alike as to resemble identical
twins.
Accordingly, mere appearance is not a safe criterion of the
identity of twins. His researches were published in the _Archives of
Philosophy, Psychology and Scientific Methods_, No. 1, New York, 1905.
[6] _A First Study of the Inheritance of Vision and the Relative
Influence of Heredity and Environment on Sight. _ By Amy Barrington and
Karl Pearson. Eugenics Laboratory (London), Memoir Series V.
[7] Dr. James Alexander Wilson, assistant surgeon of the Opthalmic
Institute, Glasgow, published an analysis of 1,500 cases of myopia in
the _British Medical Journal_, p. 395, August 29, 1914. His methods are
not above criticism, and too much importance should not be attached to
his results, which show that in 58% of the cases heredity can be
credited with the myopia of the patient. In 12% of the cases it was due
to inflammation of the cornea (keratitis) while in the remaining 30% no
hereditary influence could be proved, but various reasons made him feel
certain that in many cases it existed. The distribution of myopia by
trades and professions among his patients is suggestive: 65% of the
cases among school children showed myopic heredity; 63% among housewives
and domestic servants; 68% among shop and factory works; 60% among
clerks and typists; 60% among laborers and miners. If environment really
played an active part, one would not expect to find this similarity in
percentages between laborers and clerks, between housewives and
schoolteachers, etc.
[8] _The Influence of Unfavourable Home Environment and Defective
Physique on the Intelligence of School Children. _ By David Heron.
Eugenics Laboratory (London), Memoir Series No. VIII.
[9] _Hereditary Genius; an Inquiry into its Laws and Consequences. _
London, 1869.
[10] Woods, Frederick Adams, "Heredity and the Hall of Fame," _Popular
Science Monthly_, May, 1913.
[11] Woods, Frederick Adams, _Mental and Moral Heredity in Royalty_, New
York, 1906. See also "Sovereigns and the Supposed Influence of
Opportunity," _Science_, n. s. , XXXIX, No. 1016, pp. 902-905, June 19,
1914, where Dr. Woods answers some criticisms of his work.
[12] _Educational Psychology_, Vol. III, p. 306. Starch's results are
also quoted from Thorndike.
[13] Jean Baptiste Lamarck, a French naturalist, born in 1744, was one
of the pioneers in the philosophical study of evolution. The theory
(published in 1809) for which he is best known is as follows: "Changes
in the animal's surroundings are responded to by changes in its habits. "
"Any particular habit involves the regular use of some organs and the
disuse of others. Those organs which are used will be developed and
strengthened, those not used diminished and weakened, and the changes so
produced will be transmitted to the offspring, and thus progressive
development of particular organs will go on from generation to
generation. " His classical example is the neck of the giraffe, which he
supposes to be long because, for generation after generation, the
animals stretched their necks in order to get the highest leaves from
the trees.
[14] Boas, F. , _Changes in Body Form of Descendants of Immigrants_,
1911.
[15] _Civilization and Climate. _ By Ellsworth Huntington, Yale
University Press, 1916.
[16] _American Naturalist_, L. , pp. 65-89, 144-178, Feb. and Mar. , 1916.
[17] _Proc. Am. Philos. Soc. _ LV, pp. 243-259, 1916.
[18] Dr. Reid is the author who has most effectively called attention to
this relation between alcohol and natural selection. Those interested
will find a full treatment in his books, _The Present Evolution of Man_,
_The Laws of Heredity_, and _The Principles of Heredity_.
[19] _Principles of Psychology_, ii, p. 543.
[20] Leon J. Cole points out that this may be due in considerable part
to less voluntary restriction of offspring on the part of those who are
often under the influence of alcohol.
[21] For a review of the statistical problems involved, see Karl
Pearson. An attempt to correct some of the misstatements made by Sir
Victor Horsley, F. R. S. , F. R. C. S. , and Mary D. Sturge, M. D. , in
their criticisms of the Galton Laboratory Memoir: _First Study of the
Influence of Parental Alcoholism_, etc. ; and Professor Pearson's various
popular lectures, also _A Second Study of the Influence of Parental
Alcoholism on the Physique and Intelligence of Offspring_. By Karl
Pearson and Ethel M. Elderton. Eugenics Laboratory Memoir Series XIII.
[22] _A First Study of the Influence of Parental Alcoholism on the
Physique and Intelligence of Offspring. _ By Ethel M. Elderton and Karl
Pearson. Eugenics Laboratory Memoir Series X. Harald Westergaard, who
reexamined the Elderton-Pearson data, concludes that considerable
importance is to be attached to the selective action of alcohol, the
weaklings in the alcoholic families having been weeded out early in
life.
[23] Prohibition would have some _indirect_ eugenic effects, which will
be discussed in Chapter XVIII.
[24] Chapter XXX, verses 31-43. A knowledge of the pedigree of Laban's
cattle would undoubtedly explain where the stripes came from. It is
interesting to note how this idea persists: a correspondent has recently
sent an account of seven striped lambs born after their mothers had seen
a striped skunk. The actual explanation is doubtless that suggested by
Heller in the _Journal of Heredity_, VI, 480 (October, 1915), that a
stripe is part of the ancestral coat pattern of the sheep, and appears
from time to time because of reversion.
[25] Such a skin affection, known as icthyosis, xerosis or xeroderma, is
usually due to heredity. Davenport says it "is especially apt to be
found in families in which consanguineous marriages occur and this fact,
together with the pedigrees [which he studied], suggests that it is due
to the absence of some factor that controls the process of cornification
of the skin. On this hypothesis a normal person who belongs to an
affected family may marry into a normal family with impunity, but cousin
marriages are to be avoided. " See Davenport, C. B. , _Heredity in
Relation to Eugenics_, p. 134. New York, 1911.
[26] Its eugenics is to be effected through the mental exertion of
mothers. And we have lately been in correspondence with a western
attorney who is endeavoring to form an association of persons who will
agree to be the parents of "willed" children. By this means, he has
calculated (and sends a chart to prove it) that it will require only
four generations to produce the Superman.
[27] _Life and Letters of Charles Darwin_, Vol. I, p. 302, New York,
1897. The letter is dated 1844.
[28] Goddard, H. H. , _Feeble-mindedness_, p. 359. New York, the
Macmillan Company, 1914.
[29] For a review of the evidence consult an article on "Telegony" by
Dr. Etienne Rabaud in the _Journal of Heredity_, Vol. V, No. 9, pp.
389-400; September, 1914.
[30] It will be recalled that the coefficient of correlation measures
the resemblance between two variables on a scale between 0 and-1 or +1.
If the correlation is zero, there is no constant relation; if it is
unity, any change in one must result in a determinate change in the
other; if it is 0. 5, it means that when one of the variables deviates
from the mean of its class by a given amount, the other variable will
deviate from the mean of its class by 50% of that amount (each deviation
being measured in terms of the variability of its own class, in order
that they may be properly comparable. )
[31] Sidis, Boris, M. A. , Ph. D. , M. D. , "Neurosis and Eugenics," _Medical
Review of_ _Reviews_, Vol. XXI, No. 10, pp. 587-594, New York, October,
1915. A psychologist who writes of "some miraculous germ-plasm
(chromatin) with wonderful dominant 'units' (Chromosomes)" is hardly a
competent critic of the facts of heredity.
[32] In a letter to the _Journal of Heredity_, under date of August 4,
1916.
[33] Galton, Francis, _Inquiries into Human Faculty_, p. 167, London,
1907.
[34] Woods, Frederick Adams, _Heredity in Royalty_, New York, 1906.
[35] _Op. cit. _, pp. 170-171.
[36] Thorndike, E. L. , "Measurements of Twins," _Arch. of Philos. ,
Psych. and Sci. Methods_, No. 1, New York, 1905; summarized in his
_Educational Psychology_, Vol. III, pp. 247-251, New York, 1914.
Measured on a scale where 1 = identity, he found that twins showed a
resemblance to each other of about . 75, while ordinary brothers of about
the same age resembled each other to the extent of about . 50 only. The
resemblance was approximately the same in both physical and mental
traits.
[37] The quotations in this and the following paragraph are from
_Thorndike's Educational Psychology_, pp. 304-305, Vol. III.
[38] _Biometrika_, Vol. III, p. 156.
[39] "William of Occam's Razor" is the canon of logic which declares
that it is unwise to seek for several causes of an effect, if a single
cause is adequate to account for it.
[40] Schuster, Edgar, _Eugenics_, pp. 150-163, London, 1913.
[41] _Educational Psychology_ (1914), Vol. III, p. 235.
[42] Cobb, Margaret V. , _Journal of Educational Psychology_, viii, pp.
1-20, Jan. , 1917.
[43] This is not true of the small English school of biometrists,
founded by Sir Francis Galton, W. F. R. Weldon and Karl Pearson, and now
led by the latter. It has throughout denied or minified Mendelian
results, and depended on the treatment of inheritance by a study of
correlations. With the progress of Mendelian research, biometric methods
must be supplemented with pedigree studies. In human heredity, on the
other hand, because of the great difficulties attendant upon an
application of Mendelian methods, the biometric mode of attack is still
the most useful, and has been largely used in the present book. It has
been often supposed that the methods of the two schools (biometry and
Mendelism) are antagonistic. They are rather supplementary, each being
valuable in cases where the other is less applicable. See Pearl,
Raymond, _Modes of Research in Genetics_, p. 182, New York, 1915
[44] Few people realize what large numbers of plants and animals have
been bred for experimental purposes during the last decade; W. E. Castle
of Bussey Institution, Forest Hills, Mass. , has bred not less than
45,000 rats. In the study of a single character, the endosperm of maize,
nearly 100,000 pedigreed seeds have been examined by different students.
Workers at the University of California have tabulated more than 10,000
measurements on flower size alone, in tobacco hybrids. T. H. Morgan and
his associates at Columbia University have bred and studied more than
half a million fruit flies, and J. Arthur Harris has handled more than
600,000 bean-plants at the Carnegie Institution's Station for
Experimental Evolution, Cold Spring Harbor, L. I. While facts of human
heredity, and of inheritance in large mammals generally, are often
grounded on scanty evidence, it must not be thought that the fundamental
generalizations of heredity are based on insufficient data.
[45] For a brief account of Mendelism, see Appendix D.
[46] Of course these factors are not of equal importance; some of them
produce large changes and some, as far as can be told, are of minor
significance. The factors, moreover, undergo large changes from time to
time, thus producing mutations; and it is probable small changes as
well, the evidence for which requires greater refinements of method than
is usual among those using the pedigree method.
[47] _A Critique of the Theory of Evolution_, by Thomas Hunt Morgan,
professor of experimental zoology in Columbia University. Princeton
University Press, 1916. This book gives the best popular account of the
studies of heredity in Drosophila. The advanced student will find _The
Mechanism of Mendelian Heredity_ (New York, 1915), by Morgan,
Sturtevant, Muller, and Bridges, indispensable, but it is beyond the
comprehension of most beginners.
[48] "On the Inheritance of Some Characters in Wheat," A. and G. Howard,
_Mem. Dep. of Agr. India_, V: 1-46, 1912. This careful and important
work has never received the recognition it deserves, apparently because
few geneticists have seen it. While the multiple factors in wheat seem
to be different, those reported by East and Shull appear to be merely
duplicates.
[49] "The Nature of Mendelian Units. " By G. N.
