304 



GUY A. VOISIN AND RADSLAV KINSKY 



nothing and were followed as normal controls. The results are 

 shown in Fig. 5, where it can be seen that the repetition of 

 injections had a moderate but definite additional protective action 

 over the single injection. This additional protective action seems 

 to be effective mainly between day 14 and day 28. This is precisely 



ANIMALS TREATED WITH : 

 70 I X Homologous cells ♦ normal serum 



^ Homologous cells ♦ AN -BI serum 



(one injection) 

 vt-n Homologous cells + AN-BI 



serum(Z toz, injections) 



Nothing (normal ,.*-"' 



controls) 



Birth 

 and injection 



21 28 35 



Days after birth 



Fig. 5. Cumulative curves of mortality (same method as in Fig. i). 

 Increase in protection by one to three additional injections. Number of 

 animals aUve on day 7: 54 protected (one single injection); 52 protected 

 (one to three additional injections); 81 unprotected; 40 normal controls. 



the period during which runting is maximal in animals treated 

 with one single injection of facilitating serum at birth. 



(3) Chronology of runting 



The main facts concerning the chronology of runting in both 

 series treated with homologous spleen cells plus either normal 

 CBA serum or facilitating CBA serum, can be best expressed and 

 analysed by means of histograms giving the number of deaths per 



