49 



Immunisation by Means of Bacterial '^Endotoxins. 

 By E. Tanner Hewlett, M.D. 



(Communicated by Prof. W. D. Halliburton, F.E.S. Eeceived March 28, — 

 Eead May 4, 1911.) 



In a former paper* it was shown that the intra-cellular constituents of 

 bacterial cells, bacterial endotoxins, possess a considerable capacity for 

 increasing the opsonising action of the serum of healthy rabbits. In the 

 present paper, the action of bacterial endotoxins in immunising against 

 injections of the corresponding living organisms has been investigated. 

 Smallman, in an investigation upon the active immunisation of experimental 

 animals with typhoid cell juices,f found that the fresh fluid cell juice and 

 also the dried juice immunised guinea-pigs against injections of living 

 typhoid culture. The endotoxins were prepared in the manner described in 

 the previous paper. Guinea-pigs were the experimental animals employed 

 throughout. 



The results obtained are summarised in the following sections : — 



Immunisation against the Bacillus Typhosus. 



Series I. — Fifteen guinea-pigs were inoculated on May 14, 1909, each with 

 1 mgrm. of typhoid endotoxin prepared on May 12, 1909. 



Series II. — Fifteen guinea-pigs were inoculated on the same date (May 14) 

 each with O'l mgrm. of typhoid endotoxin (same preparation). 



Series III. — Fifteen guinea-pigs were inoculated on May 26, 1909, each 

 with O'Ol mgrm. of typhoid endotoxin (same preparation). 



Series IV. — Sixteen guinea-pigs were inoculated on May 21, 1909, each with 

 1 c.c. of Messrs. Burroughs and Wellcome's anti-typhoid vaccine (equivalent 

 to 1,000,000,000 bacilli). 



All the guinea-pigs, at the time of inoculation, weighed 250 to 300 grm. 



Of Series I, one died on May 21, two on May 22, and one on May 28, 

 leaving 11 animals for experiment. 



Of Series II, one died on May 22, and another on June 1, leaving 13 animals 

 for experiment. 



Of Series III, one died on June 2, leaving 14 animals for experiment. 



* ' Roy. Soc. Proc.,' 1909, B, vol.81, p. 325. See also ' Roy. Soc. of Med. Proc.,' April, 

 1910 (Pathological Section), p. 165, in which the effect of injections of the various 

 tuberculins and of tubercle endotoxin on the opsonising action of the serum of healthy 

 rabbits is considered. 



t ' R.A.M.C. Journ.,' April, 1905, vol. 4, No. 4, p. 424. 



VOL. LXXXIV. — B. E 



