56 Immunisation by Means of Bacterial Endotoxins. 

 Series II. — Three endotoxins. 



Table X. 



Reference No. of 

 guinea-pig. 



Endotoxin, August 11. 



Culture, 

 September 15. 



Result. 



' { 



8 



9 

 10 

 11 

 12 

 13 



-25 mgrm. typhoid 

 + -25 „ cholera 

 + 0-5 „ diphtheria 



j- 1 loop cholera 

 1 



0-5 „ typhoid 

 0-5 „ 



"1 „ diphtheria 



o -l „ 



f 1 „ cholera "1 

 10-5 „ typhoid J 



+ Dead, Sept. 16. 



+ Dead, Sept. 17. 

 + Dead, Sept. 18. 



The controls for the typhoid and the cholera were the same as in Series I, 

 Table IX. Controls for the diphtheria were as follows : G and H, O'l loop 

 diphtheria, were dead on September 17 ; Iv, - 05 loop diphtheria, was dead on 

 September 19. 



The results of these few experiments suggest that the simultaneous 

 injection of two different endotoxins does not interfere with the protection 

 conferred by either. 



Trypanosoma brucei. 



A few experiments were performed in order to ascertain whether the 

 method employed in the foregoing work is applicable to immunisation 

 against the Trypanosoma hrucei. 



Eats were inoculated, and, when the trypanosome was abundant in the 

 blood, they were killed and the blood was collected. The blood, together 

 with the spleen in some instances, was ground in the usual way, and 

 the fluid obtained was injected into healthy rats, which subsequently were 

 inoculated with living Trypanosoma brucei. One, or in some cases two 

 and three, injections of the ground material were given, but in no case was 

 any protection obtained. 



Other experiments were also performed, using the blood and triturated 

 spleen, which had been subjected to the action of a freezing mixture of 

 ether and solid carbonic acid, without grinding. It was found that this 

 freezing ruptures, and destroys the vitality of, the trypanosomes. Negative 

 results as regards protection were also obtained by this method. 



General Summary. 



The results obtained in this investigation indicate that typhoid, cholera, 

 diphtheria, and plague endotoxins confer considerable protection against 



