190 THE ACTION OF THE LIVING CELL 



words, the young born of immunized mothers ap- 

 peared superior in every way to the controls. 



These differences recorded above cannot be at- 

 tributed to differences in the germ plasm, since all the 

 animals used in these experiments were derived from 

 the same breeding stock. Further, the observed dif- 

 ferences between the offspring of non-immunized and 

 of immunized mothers were sufficiently consistent to 

 justify the conclusion that the immunization of the 

 mother to cytost is decidedly beneficial to her off- 

 spring. 



When we attempt to interpret this result, we are 

 confronted with two possibilities, for as a result of 

 the immunization we may consider that the observed 

 results evidenced by increased resistance of the young 

 are due solely to the lack of toxic effects upon the 

 embryo during intrauterine life, thus permitting a 

 normal development; or on the other hand, it may be 

 supposed that the increased resistance developed by 

 the mother is passed on to her offspring. From an 

 experimental standpoint the latter conclusion appears 

 the more likely for several reasons. 



In the first place, it has been pointed out above that 

 by immunization cats may be rendered less susceptible 

 to the respiratory disturbances which are induced by 

 keeping the animals in cytost-sprayed cages. Further, 

 it was found that in such cages the longevity of kittens 

 born of immunized mothers was greater than that of 

 those whose mothers had not been immunized. This 

 result can only be explained on the assumption that 

 the kittens during their intrauterine existence had ac- 

 quired, in a degree, the immunity induced in their 

 mothers. 



