Eugenics Committee: Studies in Human Heredity 



549 



each scientific man about 1.6. Twenty- 

 two per cent, of the famihes are child- 

 less; only one family in 75 is larger 

 than six. The same conditions obtain 

 for other college graduates. Answers 

 have been received from 461 leading 

 scientific men giving the causes which 

 led to the limitation in the size of their 

 families. One hundred and seventy-six 

 were not voluntarih^ limited, while 285 

 were so limited, the cause of the volun- 

 tary limitation being health in 133 

 cases, expense in 98 cases and various 

 other reasons in 54 cases. Childlessness 

 was involuntary in two-thirds of the 

 cases. In the standardized family of 

 two the condition is desired in six 

 cases out of seven. In over one-third of 

 the families the limitation was invol- 

 untary, due to infertility and other 

 pathological causes, but if these had not 

 obtained, voluntary limitation would 

 have occurred in nearly all or perhaps 

 in all cases." 



ALCOHOL AND HEREDITY. 



Dr. T. D. Crothers, Director of the 

 Walnut Hospital for Inebriates, Hart- 

 ford, Connecticut, is undertaking mod- 

 ern field studies among the families of 

 inebriates. 



Dr. C. H. Danforth and his associates 

 of the department of anatomy, Wash- 

 ington University, St. Louis, Mo., have 

 recently undertaken the investigation 

 of a number of lines of heredity, in 

 which anatomy plays a part. One of 

 the methods of operation is to examine 

 all subjects brought to the dissecting 

 table, for abnormalities that give prom- 

 ise of being due to heredity. When 

 such are found, living relatives of the 

 deceased are sought out, and the pedi- 

 gree made up as far as possible. The 

 problem of twinning is also being at- 

 tacked, but the results so far agree with 

 those foimd by other investigators, in 

 that they show some forms, at least, of 

 twinning to be distinctly hereditary, 

 without giving any clear light as to the 

 manner in which the tendency is in- 

 herited. It is found that the measure 

 of resemblance between twins is not a 

 safe indication whether they are homo- 

 logous ("duplicate," i.e., formed by a 

 division of the fertilized ovum at the 



stage when it consists of two cells) or 

 heterologous (ordinary twins). It is 

 possible that the two types of twinning 

 are differently inherited. 



Charles B. Davenport, director of 

 the Department of Experimental Evo- 

 lution, Carnegie Institution of Wash- 

 ington, at Cold Spring Harbor, Long 

 Island, New York, and also director of 

 the Eugenics Record Office there, has 

 been devoting particular attention dur- 

 ing the last few years to the inheritance 

 of mental traits. Many of these re- 

 searches will be described in his forth- 

 coming book, "The Feebly Inhibited," 

 which will contain, among other first- 

 hand field data, 165 family histories. 

 It is a study of the nature and control 

 of emotional impulses, with special 

 reference to criminalistic traits, the 

 manner of their inheritance, and their 

 periodicity. 



Under Dr. Davenport's immediate 

 supervision, a special study in the in- 

 heritance of stature is being made by 

 the Eugenics Record Office. The usual 

 field studies in this office continue: at 

 present they include a study of families 

 that have produced many of America's 

 most effective men, with special refer- 

 ence to the origin of their distinctive 

 traits; and a further study of the Jukes 

 family, that famous cacogenic group in 

 the state of New York, which Dugdale 

 brought to light 40 years ago. A. H. 

 Estabrook, who unearthed the history 

 of the "Nam" family, a somewhat 

 similar group, a few years ago, has taken 

 up the present status of the Jukes, in 

 order to observe the changes that have 

 taken place in them as they have be- 

 come scattered over the country during 

 recent years. It is interesting to find 

 that a few branches which are far from 

 the original environment have produced 

 excellent and prosperous citizens — pos- 

 sibly as the result of some fortunate 

 marriage in the previous generation. 

 On the whole, however, this great tribe 

 continues to furnish an almost unparal- 

 leled record of continuous inefficienc3% 

 from a social point of view. 



consanguineous marriage. 



The study of consanguineous marri- 

 ages and their consequences, as observed 



