STUDIES ON CYTOLYSINS 



79 



with lens of Peromyscus maniculatus gambeli, though the two 

 subspecies of maniculatus (sonoriensis and rubidus) stood much 

 closer to gambeli than did any of the others. This bears out the 

 relationships as established by taxonomists. Reithrodontomys 

 megalotis longicauda, the long-tailed harvest-mouse, which be- 

 longs to the same family as Peromyscus, gave a slight reaction, 

 while Perognathus fallax fallax, the short-eared pocket-mouse, 

 of an entirely different family, gave only negative results. 



Effects of antibodies on the fetus 



In attempting to get cytolytic effects on the young in utero, 

 sixteen mice which had previously been mated for the purpose or 

 which were obviously pregnant were used. Of these five proved 



TABLE 5 



not to be pregnant, leaving eleven for the test. Two of these, 

 used as controls, were injected with serum from a normal, non- 

 sensitized fowl, so that nine were available for injection with 

 the cytolytic serum. It will be seen from table 5 that the 

 mortality was heavy and that only females which were well 

 advanced in pregnancy and which, therefore, got but one or two 

 doses of serum, brought forth their young. At each treatment 

 every female was injected with 1 cc. of the sensitized serum. 



Species of Peromyscus maniculatus gambeli only were used. 

 The period of gestation in this form is twenty-one days and the 

 young do not open their eyes until about sixteen days after birth. 



It will be seen from table 5 that only three (Nos. 3, 4, and 5) 

 of the females injected with the sensitized serum survived and 

 bore young. Of these. No. 3 lost one of her young a few days 



