188 THE ACTION OF THE LIVING CELL 



of fifty per cent within a year when kept under the 

 same conditions in his animal house. These results 

 of Dr. Banzhof offer striking confirmation of the 

 writer's results with cats (page 112), and again 

 demonstrate that it is possible to raise the natural 

 resistance of animals by a properly graded series of 

 cytost injections. Unfortunately Dr. Banzhof did 

 not record the gain in weight of his animals; there- 

 fore we cannot compare this aspect of their growth 

 with that of controls, as was done in the writer's experi- 

 ments with cats. 



Old guinea pigs were found to be less resistant to 

 injections of large quantities of cytost than younger 

 animals. This fact may be taken as indicative of the 

 fact that the older animals suffer from a greater ac- 

 cumulation of cytost than do the younger ones; con- 

 sequently the former are more apt to die as a result 

 of the toxemia of pregnancy than the latter, a conclu- 

 sion in agreement with observations from experience. 

 That older animals actually are more sensitive to cy- 

 tost is evidenced in that they succumb more rapidly to 

 injections of large quantities of cytost than do younger 

 animals. 



Turning now to the influence of the immunization 

 of the mothers on the offspring, we have found the 

 following: When female guinea pigs receive a series 

 of immunizing cytost injections, as above described, 

 but given prior to pregnancy, it is found that the off- 

 spring are more vigorous, have a healthier appetite, 

 grow more rapidly, and present a healthier appear- 

 ance than do the offspring of non-immunized animals. 

 A series of young females was divided into two groups, 

 one being immunized and the other held as control. 



