308 MANUAL OF BACTERIOLOGY. 



of the disease, and probably in a majority. Typhoid bacilli 

 frequently appear in the urine (in about twenty per cent, 

 of all cases) and the examination of urine for them has 

 been used in diagnosis. The bacilli often occur in the 

 gall-bladder. They have been found associated with gall- 

 stones, and have been supposed to be one of the causes 

 for the formation of gall-stones. 1 They may remain pres- 

 ent in the gall-bladder or in the urine 2 long after convales- 

 cence from the disease. They have been demonstrated in 

 the " rose spots " on the abdomen. They may be present 

 in the lesions of the pneumonia, which frequently compli- 

 cates typhoid fever, and may appear in the sputum. 



Inoculation experiments in animals have not been very 

 satisfactory. With a few exceptions, possibly, anatomical 

 lesions resembling those of typhoid fever have not been 

 produced by the inoculation of typhoid bacilli into animals. 

 The injection of cultures into animals may produce death, 

 but it can usually be shown to have resulted from the poisons 

 contained in the cultures. 



Typhoid fever is rare during the first two years of life. 

 It frequently attacks young and robust men. The causes 

 that bring about susceptibility to infection are not known. 



The principal lesion in typhoid fever lies in the Peyer's 

 patches of the lower part of the small intestines; the mes- 

 enteric lymph-nodes and spleen also are swollen. The 

 typhoid bacillus may be demonstrated in sections of the 

 walls of the diseased portions of the intestine. Cases are 

 recorded in which no lesions were found in the intestines 

 but where the typhoid bacilli were widely spread through 

 the organs of the body, and which therefore represented 

 typhoid septicemia. 



Periostitis and osteomyelitis, which are not uncommon 

 sequelae of typhoid fever, may be caused by typhoid bacilli. 



1 Pratt, American Journal Medical Sciences, Vol. 122, 1901. 



2 M. \Y. Richardson, Journal Experimental Medicine, Vol. IV., 1899. 



