'482 Chapter XV 



doses of typhoid cultures) quite comparable to the properties 

 discovered by them in the serum of persons who had recovered from 

 typhoid fever. Pfeiffer and Kolle believed that they thus had a 

 proof of the refractory condition of the individuals whom they had 

 submitted to these injections. 



These experiments were continued by Wright, Professor of 

 Pathology at Netley, and it is owing to his unwearied efforts that 

 science finds herself in possession of very important evidence on the 

 subject of protective inoculations against typhoid fever in man. 

 According to a verbal communication made to me by Wright, he 

 [505] has up to the present distributed more than 300,000 doses of his 

 antityphoid vaccine. This vaccine he prepared in the following way 1 . 

 The typhoid coccobacillus is sown in carefully neutralised broth 

 containing 1% of peptone. The flasks of culture are kept in the 

 incubator at about 37 C. for two or three weeks, after which their 

 contents are transferred to large flasks in order to be submitted to a 

 temperature of 60 C. This temperature is quite sufficient to kill all 

 the coccobacilli, but for greater surety Wright added to his cultures 

 one-tenth of their volume of a 5 % solution of carbolic acid or of 

 lysol. The vaccine, thus prepared, is examined as to its toxicity 

 for the guinea-pig by means of subcutaneous injections. Wright 

 injects into man a dose of vaccine which is sufficient to kill 

 100 grammes of guinea-pig (of the weight of 250 to 300 grammes). 

 This dose often amounts to half a cubic centimetre, but it may 

 have to be increased to 1 c.c. and even 1*5 c.c. 



The inoculations are made below the skin of the flank or in 

 the shoulder. They are followed by a rise of temperature which 

 commences as early as two or three hours after the injection. This 

 fever is accompanied by pains in the back, nausea, and want of 

 appetite. There may even be collapse ; this led Wright to keep his 

 patient in bed for some time after the vaccinal injection. Besides 

 this reaction, there occurs, at the seat of inoculation, a swelling and 

 redness, accompanied by pain ; as a rule all these symptoms have 

 disappeared by the end of 48 hours. 



Wright convinced himself that the blood serum of individuals 

 treated by his vaccine, at the end of a certain time acquires the 

 property of agglutinating typhoid coccobacilli in a variable, but 

 usually very marked degree. He even thought that this property 



1 Wright and Irishman, Brit. Med. Journ., London, 1900, Vol. i, p. 122; [Wright, 

 "A short treatise on anti-typhoid inoculation," London, 1904]. 



