344 TYPHOID FEVER 



showed a case incidence of 2'25 per cent, with a case mortality 

 of 12 per cent; in the remaining 41,000 uninoculated the case 

 incidence was 5 '75 per cent and the case mortality 21 per cent. 

 The best results seemed to be obtained when ten days after the 

 first inoculation a second similar inoculation is practised. 

 Wright has found that in certain cases immediately after 

 inoculation there is a fall in the bactericidal power of the blood 

 (negative phase), and he is of opinion that this indicates a 

 temporary increased susceptibility to the disease. He therefore 

 recommends that when possible the vaccination should be carried 

 out some time previous to the exposure to infection. There can 

 be very little doubt that in this method an important prophy- 

 lactic measure has been discovered. 



Antityphoid Serum. Chantemesse lias immunised animals with dead 

 cultures of the typhoid bacillus, and having found that their sera had 

 protective and curative effects in other animals, has used such sera 

 in human cases of typhoid with apparent good result. In the hands 

 of others, however, such a line of treatment has not been equally 

 successful. 



Methods of Examination. The methods of microscopic 

 examination, and of isolation of typhoid bacilli from the spleen 

 post mortem, have already been described. They may be isolated 

 from the Peyer's patches, lymphatic glands, etc., by a similar 

 method. 



During life, typhoid bacilli may be obtained in culture in the 

 following ways : 



(a) From the Spleen. This is the most certain method of 

 obtaining the typhoid bacillus during the continuance of a case. 

 The skin over the spleen is purified and, a sterile hypodermic 

 syringe being plunged into the organ, there is withdrawn from 

 the splenic pulp a droplet of fluid, from which plates are made. 

 In a large proportion of cases of typhoid the bacillus may be 

 thus obtained, failure only occurring when the needle does not 

 happen to touch a bacillus. Numerous observations have shown 

 that, provided the needle be not too large, the procedure is quite 

 safe. Its use, however, is scarcely called for. 



(b) From the Urine. Typhoid bacilli are present in the urine 

 in at least twenty -five per cent of cases, especially late in the 

 disease, probably chiefly when there are groups in the kidney 

 substance. For methods of examining suspected urine, see 

 p. 69. 



(c) From the Stools. During the first ten days of a case of 

 typhoid fever, the bacilli can be isolated from the stools by the 

 ordinary plate methods preferably in MacConkey's lactose bile 



