BACILLUS OF TYPHOID FEVER 415 



Excluding water and milk, all remaining causes of typhoid dissemi- 

 nation constitute about twelve per cent and are found chiefly in the 

 use of vegetables contaminated from infected soil, and other food prod- 

 ucts. Recently Conn l suggested that oysters grown in waters close 

 to sewage discharges may be the means of typhoid transmission. An 

 epidemic at Wesleyan University was traced to this cause. Experi- 

 ments by Foote 2 demonstrated that typhoid bacilli may be found 

 alive within oysters for three weeks after they disappeared from the 

 surrounding water. The importance of this mode of infection is un- 

 certain. Rosenau, Lumsden, and Castle 3 found it to be negligible in 

 the District of Columbia. 



Indirect contamination of food and water by the intermediation of 

 flies and other insects has been emphasized by Veeder 4 and is unques- 

 tionably of great importance. 



Typhoid Carriers. One of the important factors in the spread 

 of typhoid fever is the existence of a considerable number of "car- 

 riers ' ' in every community. These are individuals who harbor typhoid 

 bacilli in their intestinal canals, probably with a nidus in the gall 

 bladder. They may intermittently or continually discharge typhoid 

 bacilli with the feces and therefore be a constant menace to others. 

 There are now a considerable number of well-known cases where series 

 of small epidemics have been started by carriers, and in the mobiliza- 

 tion of armies the incorporation of carriers with troops may be a seri- 

 ous menace. 



Carriers may be discovered by isolation of the bacilli from the 

 feces as described in another place. 



Poisons of the Typhoid Bacillus. The investigation of the toxic 

 products of the typhoid bacillus has occupied the attention of a large 

 number of workers. The first to do experimental work upon the sub- 

 ject was Brieger 5 soon after the discovery and cultivation of the micro- 

 organism. That toxic substances can be obtained from typhoid cultures 

 is beyond question. There is, however, a definite difference of opinion 

 as to whether these poisons are so-called endotoxins only, or whether 

 they are in part composed of soluble toxins comparable to those of 

 diphtheria and tetanus, following the injection of which antitoxic sub- 

 stances may be formed. 



The evidence so far seems to bear out the original contention of 



1 Conn, Med. Record, Dec., 1894. 2 Foote, Med. News, 1895. 



3 Rosenau, Lumsden, and Castle, Bull. 52, Hyg. Lab. U. S. Pub. Health Service, 1908. 



Veeder, Med. Record, 45, 1898. B Brieger, Deut. med. Woch., xxvii, 1902. 



