438 INFECTION AND IMMUNITY. 



It is possible to establish the diagnosis of 

 cultures, typhoid fever by cultivating the bacilli from the 

 blood, even before the serum has developed suffi- 

 cient agglutinating power to cause agglutination. 

 A small flask of bouillon is inoculated with from 

 1 to 5 c.c. of blood, drawn from the median vein 

 of the arm, and after twenty-four hours of incu- 

 bation a small portion of it is plated out. Colonies 

 which develop on the plates may be identified by 

 the usual bacteriologic methods, or the agglutina- 

 tion test may be performed with a known anti- 

 typhoid serum. After from the tenth to the four- 

 teenth day the organisms can rarely be cultivated 

 from the blood; the bactericidal substances and 

 phagocytic power of the blood may have so 

 increased by this time that circulating bacilli are 

 killed rapidly. 



In from one-fourth to one-third of the cases, in 

 the third week, or during convalescence, the bacilli 

 appear in large numbers in the urine, in which 

 they may persist for many weeks. According to 

 Kan ja jeff, they are discharged into the urine from 

 metastatic foci in the kidneys. 



Many of the symptoms, complications and se- 

 quelaa of typhoid fever, as the rose-spots, enlarged 

 spleen, bone lesions, and in some instances nervous 

 lesions and pneumonia, depend on the distribution 

 of the bacilli. This is in contrast to the conditions 

 in diphtheria and tetanus, in which the distribu- 

 tion of the bacilli is of little significance for the 

 involvement of particular organs. The anatomic 

 changes and clinical symptoms suggest that the 

 lymphoid tissue and central nervous system have 

 a special affinity for the toxic constituents of the 

 typhoid bacilli. 



