BACILLUS OF TYPHOID FEVER 405 



not only remain latent for a long time in the gall-bladder of rabbits, 

 but would appear in the blood stream with considerable regularity 

 after the seventh or ninth day, and persist for as long as 125 days. 

 Gay and Claypole ^ have been able to produce the carrier state in 

 rabbits with great regularity by growing the typhoid cultures used for 

 inoculation upon agar containing 10 per cent defibrinated rabbit's 

 blood. Such cultures are not as readily agglutinated by immune serum 

 as are those grown on plain agar, and it may well be that they have 

 acquired a certain degree of resistance to the serum antibodies which 

 renders them more competent to survive in the body of the rabbit. 

 Gay has used rabbits inoculated with such cultures for the determination 

 of the efficacy of his sensitized vaccines. 



In man the overwhelming majority of typhoid infections take the 

 form of the disease clinically known as typhoid fever. For a descrip- 

 tion of the clinical course and pathological lesions of the disease, the 

 reader is referred to the standard text-books of medicine and pathology. 

 During the course of the disease, and during convalescence, the bacilli 

 may be cultivated from the circulating blood, the rose spots, the feces, 

 the urine, and in exceptional cases from the sputum. At autopsy the 

 bacilli may be obtained from these sources as well as from the lesions in 

 the intestine, the spleen, and often from the liver, kidneys, and from the 

 gall-bladder. 



Though formerly regarded as primarily an intestinal disease, recent 

 investigations have brought convincing proof that the disease is in its 

 inception actually a bacteriemia. It is not unlikely that the intestinal 

 lesions are largely the result of toxic products which are excreted 

 through the intestinal wall. 



Typhoid Bacilli in the Blood during the Disease. — The investigations 

 of many workers have shown that typhoid bacilli are present in the 

 circulating blood of practically all patients during the early weeks of the 

 disease. Series of cases have been studied by Castellani,^ Schottmul- 

 ler,^ and many others. More recently Coleman and Buxton* have 

 reported their researches upon 123 cases, and have at the same time 

 analyzed all cases previously reported. Their analysis of blood cultures 

 taken at different stages in the disease is as follows : 



^Gay and Claypole, Arch, of Inf. Med., Dec, 1913. 



^ Castellani, Riforma medica, 1900. 



' Schottmiieller, Deut. med. Woch., xxxii, 1900, and Zeit. f. Hyg., xxxvi, 1901. 



* Coleman and Buxton, Am. Jour, of Med. Sci., 133, 1907. 



