ON THE DOMESTIC FOWL. 255 



be the case) they are bound presently to become very convincing to 

 such persons as are not prevented by prejudice from accepting or 

 appreciating scientific evidence on the problem of the effect of paren- 

 tal alcoholism upon the progeny. 



We may evaluate our results in general terms as follows : 



1. There is no evidence that specific germinal changes have been 

 induced by the alcoholic treatment, at least in those germ cells which 

 produced zygotes. 



2. There is no evidence that the germ cells zuJiich produced 

 zyygotes have in any respect been injured or deleteriously affected. 



3. The results with poultry are in apparent contradiction to the 

 results of Stockard, Cole and others with mammals. I believe, for 

 reasons which will presently appear, that this contradiction is only 

 apparent and not real, paradoxical as such a statement may appear. 



4. The results with poultry are in a number of important respects 

 in essentially complete agreement with those of Elderton and Pear- 

 son* on parental alcoholism in man, and of Nice^ in mice. 



The interpretation of these results which seems to account best 

 for all the facts is that the apparent discrepancy between the avian 

 and mammalian results is fundamentally due to a difference in 

 degree of resistance of the germ cells to alcohol. On this basis it is 

 possible, I believe, to frame an hypothesis which will bring together 

 in a satisfactory manner under one point of view the apparently 

 discrepant results of Stockard, Pearson, Nice and the writer. 



At the outstart let us remind ourselves of a point which one is 

 apt to overlook in considering results of this sort, namely that the 

 germ cells which produce the zygotes, which are the progeny of our 

 experiments, are only a very minute fraction of all the germ cells 

 which the parents produce. Let X be the total number of germ 

 cells (ova or spermatozoa) which the individual produces, and let a 

 be the number which succeed in taking part in the formation of 



* Elderton, E. M., and Pearson, K., " A First Study of the Influence of 

 Parental Alcoholism on the Physique and Ability of the Offspring," Eugenics 

 Lab. Mem., X., pp. 1-46, 1910. (Second edition.) 



5 Nice, L. B., " Comparative Studies on the Effects of Alcohol, Nicotine, 

 Tobacco Smoke, and Caffeine on White Mice. I. Effects on Reproduction 

 and Growth," Jour. E.vper. ZooL, Vol. 12, pp. 133-152, 1912. 



