276 THE TREND OF THE RACE 
to one another, the apparent discrepancy being due to the differ- 
ent degrees of resistance of the bird and the mammalian germ 
cells to alcohol. Where the direct injury to the germ plasm is not 
too great the action of alcohol in eliminating the weaker germ 
cells may outweigh its direct injury to the more vigorous ones. 
This, if I understand it, is the essential feature of Pearl’s attempt 
to harmonize his own results with those obtained with guinea 
pigs. Stockard points out that there may have been in Pearl’s 
experiments, not so much an elimination of weaker germ cells, as 
a very early prenatal mortality, which would naturally be mis- 
taken for infertility of the eggs. Such early mortality was ac- 
tually demonstrated in the guinea pigs, especially in the alcoholic 
strains. But, however this somewhat difficult problem may be 
solved,—whether elimination occurs before or soon after the germ 
cells unite,—both Pearl’s and Stockard’s results may be due to a 
tendency of alcohol to act injuriously on the germ plasm. The 
influence of alcohol on the race, however, is very different accord- 
ing to whether or not the direct injury of alcohol to the germ 
plasm is outweighed by its operation as a selective agent. 
Confirmatory evidence of the effect of alcohol on the germ 
cells is afforded by the experiments of Cole and Davis on rabbits 
by means of double matings. When females were mated at 
nearly the same time with normal and with alcoholized sires it was 
found that the sperm of the males that had been given alcohol 
usually failed to fertilize the ova, owing probably to the influence 
of alcohol on the vitality of the spermatozoa. 
In regard to the hereditary influence of alcohol in man our 
evidence is less direct and less conclusive. The great majority of 
writers on the relation of alcohol to heredity are firmly convinced 
that the evil effects of alcoholism are transmitted from parents to 
their children. In recent years, however, expression of opinion on 
the part of the more scientific students of the subject has become 
rather more guarded, and by a few writers, prominent among 
whom is Dr. G. A. Reid, it is held that parental alcoholism has no 
appreciable influence on the next generation. No critically 
minded and unbiased person who has become well acquainted 
