302 Maine Agricultural Experiment Station. 1917. 



b. In the intensity of dosage employed in inhalation ex- 

 periments alcohol does not destroy or functionally inactivate 

 all germ cells. The proportionate number of the whole popula- 

 tion of germ cells which w^U be inactivated by such dosage may 

 fairly be supposed to depend upon the mean absolute vigor or 

 resisting power characteristic 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. 



c. Besides the germ cells which are wholly inactivated by 

 the deleterious agent, and which we may designate as class (a), 

 we may fairly assume that there is a possibility of two other 

 classes existing, viz., (b) germ cells which, while not completely 

 inactivated, are so injured by the agent as to produce zygotes 

 which are measurably defective in some degree, and (c) germ 

 cells which are not measurably affected by the agent at all in the 

 dosage employed, and produce zygotes which are not discernibly 

 otherwise than perfectly normal. 



d. It appears entirely fair to assume that germ cells of 

 the (a) class are of relatively the lowest mean vigor or resisting 

 power, .class (b) next, and class (c) the highest. The propor- 

 tionate number of the two sorts of zygotes corresponding to 

 classes' (b) and (c) of germ cells which would be expected to 

 appear in any experiments made to test the point would clearly 

 be a function of the mutual relationship or proportionality be- 

 tween two variables, the dosage of the deleterious agent on the 

 one hand, and the mean absolute resisting power of the germ 

 cells characteristic of the strain or species of animal used in 

 the experiments on the other hand. 



e. If the dosage of the agent be relatively high in pro- 

 portion to the mean absolute resisting power it would be ex- 

 pected that all the germ cells would fall into classes (a) and 

 (b), producing no zygotes at all or zygotes in some degree de- 

 fective. This about represents the condition, so far as can be 

 judged from the data given, with Stockard's alcoholized guinea 

 pigs arid Weller's lead-poisoned guinea pigs. The dosage is 

 sufficiently high in proportion to the absolute germinal resist- 

 ing power that all or practically all of the offspring are defec- 

 tive in greater or less degree and in reference to some one or 

 more characters. Stockard's F., and F, results indicate that 



