142 
Spirochaetosis 
Exps. 5, 6. 18th Nov. 1910. Gviioea-pig injected intra-peritoneally with 2 c.c. 
of defibrinated relapsing fever blood. 
Examined with negative results on the 19th, 20th, 22nd, 24th, 25th and 26th 
Nov. 1910. 
1st Dec. 1910. Intra-peritoneal injection of 1 c.c. of defibrinated relapsing fever 
blood. Examined on next two days with negative results. 
Exp. 7. 18th Nov. 1910. White rat, intra-peritoneal injection of 1‘5 c.c. of 
defibrinated relapsing fever blood, diluted with an equal quantity of sterile saline, 
two hours after having been taken from patient. 
Examined with negative results on the 19th, 20th, 22nd, 24th and 26th 
Nov. 1910. 
Exps. 8-10. 18th Nov. 1910. White rat, injected intra-peritoneally with 
l'5c.c. defibrinated relapsing fever blood. 
Examined with negative results on the 19th, 20th, 22nd, 24th and 25th Nov. 
On this date it was re-injected, also intra-peritoneally, with 1 c.c. of defibrinated 
relapsing fever blood diluted with 2 c.c. of sterile saline. 
Examined with negative results on the 26th, 27th and 29th Nov. 
1st Dec. 1910. Injected intra-peritoneally with 1 c.c. of defibrinated relapsing 
fever blood diluted with 2 c.c. of sterile saline. 
Examined with negative results on the next two days. 
Exp. 11. 18th Nov. 1910. White rat injected intra-peritoneally with 1-5 c.c. 
of defibrinated relapsing fever blood. 
Examined wuth negative results on the 19th, 20th, 22nd and 24th Nov. 1910. 
Exp. 12. 19th Nov. 1910. Mouse, injected intra-peritoneally with 0’5 c.c. 
of defibrinated relapsing fever blood, which had been kept 24 hours on ice. 
Examined with negative results on the 20th and 22nd Nov. Died next day. 
Exps. 13-15. 25th Nov. 1910. Three mice; each received an intra-peritoneal 
injection of 0'5 c.c. of defibrinated relapsing fever blood in 1'5 c.c. saline. 
Examined with negative results on the 26th, 27th, 29th Nov. and 2nd Dec. 1910. 
Exps. 16-19. 1st Dec. 1910. Four mice each injected intra-peritoneally with 
0‘5 c.c. defibrinated relapsing fever blood in 0'5 c.c. saline. 
Examined with negative results the next and following day. 
It might be argued from the foregoing experiments that the 
negative results of the inoculations were due to the animals being 
immune. This was not the case, because the animals of experiments 
Nos. 7, 8-10, 11, 18, 14, 15 proved themselves susceptible to injections 
carried out later on, as the following experiments will show. 
11. Experiments in which infection succeeded only after repeated attempts. 
Exp. 20. Same rat as in Exp. No. 7. 2nd Dec. 1910. Intra-peritoneal 
injection of 0'3 c.c. defibrinated relapsing fever blood in 0'7 c.c. saline. 
The next day a few spirochaetes were seen in the blood, but they had disappeared 
the following day. 
