MODIFICATION OF THE GERM-CELLS IN MAMMALS 219 



action on the germ cells. This is the point of actual importance 

 and the one of chief interest from the standpoint of these ex- 

 periments. We are not here studying the alcohol problem from 

 a social standpoint and it is immaterial whether the progeny be 

 benefited or injured by the treatment of parental generations. 

 Our interest lies in whether or not the germ cells are modified 

 by the chemical treatment and whether the modification is of 

 such a nature as to alter the qualities of the individuals which 

 may compose the subsequent generations. 



Pearl, of course, fully agrees with such a position, and states 

 C16a, p. 258): 



Our results seem to me to be supplementary to those of Stockard, 

 and to throw an interesting light on the need for caution in reac ing 

 a correct interpretation of all experiments in which a mildly deleterious 

 agent acts upon the organism. 



He also believes that his results are in no way contradictory to 

 ours, but recognizes the fact that, although the same chemical 

 substance may act upon the germ plasm of two different cesses 

 of animals, the visible response on the part of the animals need 

 not necessarily be the same. In other words, one is not always 

 within the realm of legitimate scientific speculation who assumes 

 that since a given substance acts to induce a certain response 

 on the part of one animal species that the same substance will 

 call forth a like response on every other species. ''What is one 

 man's food is another man's poison." With this we fully agree; 

 it is dangerous to draw universal deductions from experiments 

 on any one or two classes of animals. 



Another possibility also recognized b}^ Pearl presents itself in 

 considering the opposite effects of the alcohol treatment on the 

 progeny of guinea-pigs and fowls. Small doses of many sub- 

 stances, one of which is alcohol, may form a physiological stand- 

 point produce a stimulating effect, while larger doses produce 

 decided depression. There is a. possibility that the same may 

 be true of the action of such substances on the germ cells. Pearl 

 has discarded such an explanation after very fair consideration, 

 and is possibly right in so doing. The experiences, however, 

 with the guinea-pigs makes our opinion decidedly prejudiced in 



