256 PEARL— EFFECT OF CERTAIN POISONS 



a zygote, and let A be the number which do not so succeed. Then, 

 of course, A^=X — a, or put the other way about, 



X=A-\-a. 



This is the fundamental gametic equation. We know that A is 

 enormously greater than a. There is furthermore a great deal of 

 evidence that a is not a random sample of X, but on the contrary is a 

 highly selected sample. To Roux in his *' Kampf der Theile " is to 

 be given the credit for first pointing out what now seems axiomatic, 

 that there is constantly going on a struggle for survival among the 

 cells of the organism, the physiologically " best " being the survivors. 

 To the philosophical breeder of animals nothing seems more cer- 

 tainly established than that this process of selection is constantly 

 going on and is of very special importance among the germ cells. 

 Direct and convincing observational and experimental proof of it 

 has been given by the double mating experiments which Cole and 

 Davis and Cole and Bachhuber have carried out. 



Granting the existence of variation in the vigor or resisting 

 power of germ cells we have the necessary basis for the action of a 

 selective agent. The hypothesis which we wish to suggest is that 

 alcohol acts as such a selective agent upon the germ cells of alco- 

 holized animals. The essential points in such an hypothesis may be 

 put in the following way. 



1. Assume the relative vigor, or resisting power of germ cells 

 varies or grades continuously from a low degree, say i, to a high 

 degree, say lo, and further assume that the absolute vigor of the 

 whole population of germ cells, measured by the mean let us say, 

 is dififerent for different species. 



2. In the intensity of dosage employed in inhalation experiments 

 alcohol does not destroy or functionally inactivate all germ cells. 

 The proportionate number of the whole population of germ cells 

 which will be inactivated by such dosage may fairly be supposed to 

 depend upon the mean absolute vigor or resisting power character- 

 istic of the particular species or strain used. In a species with germ 

 cells of absolutely low mean vigor proportionately more will be 

 functionally inactivated than in a species of high absolute mean 

 vigor of germ cells. 



3. Besides the germ cells which are wholly inactivated by the 



