146 CARNEGIE INSTITUTION OF WASHINGTON. 



one or more college men, and may be used as a basis of comparison 

 within that range. The base, 3,538, includes all recorded individuals, 

 a very large proportion of whom could not possibly have had a college 

 record. Such are practically all the females, since in former years col- 

 lege courses were not open to women, and those males who died before 

 the age of, say, 20 years. A more correct working-base would, there- 

 fore, be found by confining ourselves to the eligibles, that is, all men who 

 have attained the age of 20. At present it is possible only to approx- 

 imate the number of eligibles, which appears to be about 1,500, of 

 whom, therefore, 34.5 per cent were college graduates. Among these, 

 however, some lines show a much higher incidence of college men than 

 others. Thus, in one branch, which we may designate as the W branch, 

 there are more than 180 related individuals, of whom there appear to 

 be not more than 12 who are college men, making less than 6f per 

 cent, and in reality probably less than 1 per cent, since a large portion 

 of this branch has been dropped because entirely lacking in college 

 graduates. Of these 180, about 65 were eligible for college, hence 

 something less than 18.5 per cent of those who could have gone to 

 college actually went. 



In the closely related G branch, from which scarcely any were 

 dropped because of lack of college men, we have about 615 individuals, 

 of whom 306 were eligible for college and about 121 actually attended, 

 making thus 19.6 per cent of the whole branch, or 39.5 per cent of those 

 eligible, that actually went to college. Other branches would show 

 similar wide variation. 



Moreover, comparing the W and G branches as to eminence, we find 

 that, of the 12 Ws who went to college, one is in Who's Who in America 

 (vol. 10) and one in National Cyclopedia of American Biography, 

 making 16f per cent of the college men of this branch who attained to 

 sufficient distinction to be included in one of these publications. Of 

 the 121 in the G's who actually entered college, 25 are mentioned either 

 in the National Cyclopedia of American Biography or in Who's Who in 

 America (vol. 10), making 20.6 per cent of the college men in this 

 branch who attained to this degree of distinction. These facts appear 

 to indicate that in the G branch we are dealing with a group of higher 

 average intellectual ability than in the W branch. 



PLURAL BIRTHS. 



The Director attempted to secure light on the matter of plural births, 

 especially twinning, in man. This is a matter of considerable interest, 

 since about 1 per cent of all human births are twin births. These 

 twin births are of two types, namely, those derived from two eggs ovu- 

 lated simultaneously or nearly so, and those derived from a single egg 

 which has formed two embrj^os. In the former case, each embryo is 

 enveloped in its own chorion; in the latter, both embryos are enveloped 



