34 Mr. W. Heape. Proportion of the Sexes produced [Sept. 30, 



agents on the ovarian ova. The evidence I have to offer in the following 

 paper is, I think, strongly confirmatory of this view. 



1. Data dealt with.— From a statistical point of view, human beings are 

 the only mammals for which sufficiently large numbers can be obtained with 

 any hope of ensuring sufficient accuracy, and for these there has always been 

 difficulty in assuring oneself of the completeness of the records at any one 

 time for more than one race. When, therefore, my friend, Dr. F. H. H. 

 Ouillemard, pointed out to me that the publications of the chief sanitary 

 .officer of Cuba supplied separate details of the births and still-births of 

 whites and coloured people in the island, and that these records were further 

 subdivided into legitimate and illegitimate births and still-births, I commu- 

 nicated with that officer (Dr. Finlay), and he has very kindly supplied me 

 with a complete series of his monthly publications for the years 1904-5-6. 

 It is with these records I now deal. The numbers dealt with amount to — 



Births— whites, 131,721 ; coloured, 39,576. Total, 171,297. 

 Still-births— whites, 4160 ; coloured, 2247. Total, 6407. 

 Total production— whites, 135,881 ; coloured, 41,823. Total, 177,704. 

 Deaths— whites, 52,087 ; coloured, 27,877. Total, 79,964. 

 Marriages— whites, M. 31,481, F. 31,240; coloured, M. 7598, F. 7839. 

 Total, M. and F. (each) 39,079. 



These totals are arrived at from monthly records, for each of these three 

 years, for each of the six provinces into which the island is divided ; and in 

 each case, except for marriages, the proportion of M. per 100 F. has been 

 calculated. Altogether I have drawn up 64 tables of these and similar 

 details ; they are dealt with more fully elsewhere, the results thus obtained I 

 now summarise. 



2. The Racial Proportion of the Sexes. — The first prominent fact 

 demonstrated is the difference in the proportion of the sexes produced by the 

 two races. The whites produce a larger proportion of M. than the coloured 

 people. For whites, the proportion varies during these three years from 

 106-8 to 110-52, in the total it is 108-44 M. per 100 F. ; for coloured, the 

 proportion varies from 101 to 101-2, total 101-12 M. per 100 F. ; and this 

 racial difference is shown both for births and still-births. 



Here, then, we have a marked racial difference which, after examination of 

 other statistics of coloured people and of the inhabitants of Spain (from 

 whence most of the white inhabitants of Cuba originally came), I am of opinion 

 may confidently be assumed to show that, in this particular, the influence of 

 heredity is clearly demonstrated. 



3. The Sexual Ratio in Legitimate and Illegitimate Births. — The second 



