300 



GUY A. VOISIN AND RADSLAV KINSKY 



day 7 and day 14, at the time when runting is maximum in 

 unprotected animals. Between day 14 and day 21 it is less power- 

 ful, while the rate of death by runting is decreasing in unprotected 

 animals. Between day 21 and day 28 the protection of treated 



ANIMALS TREATED WITH 



70 Homologous cells 



♦ normal serum 





60. 

 50, 

 40 

 30 

 20 

 10 

 



-2Cl 



Homologous cells ■ 

 facilitating serum 

 Nothing (normal 

 controls) 



Birth 

 and injections 



21 28 35 



Days after birth 



Fig. I. Cumulative curves of mortality (expressed in percentage of 

 deaths) starting at day 7. The number of animals ahve on day has been 

 compared to the number of animals alive on day 7 and expressed as 

 negative entities (see text). Number of animak alive on day 7: 184 

 "protected" (i.e. injected with homologous cells plus faciHtating serum) ; 

 149 "unprotected" (i.e. injected with homologous cells plus normal 

 serum) ; 76 normal controls. For statistical significance of the differences 



see Table I. 



animals is much less powerful due to the fact that, while their death 

 rate is about the same as the week before (or a httle less), the death 

 rate of unprotected animals has now strikingly decreased. 



Finally, between day 28 and day 3 5 there is almost no death in 

 protected animals, while the death rate of unprotected animals is 

 about the same as the week before. All the preceding information 



