BACILLUS OF TYPHOID FEVER 415 



recorded, were attributable to milk. Actual discovery of Bacillus ty- 

 phosus in milk by Vaughan, Conradi, and others has been discussed in 

 another section (see page 685). The fact that this bacillus causes no 

 visible modifications in milk makes this source especially insidious. 

 When contamination of milk has occurred, it has often been traceable 

 to the water used in washing the cans or to attendants employed at 

 the dairies, who had been in contact with typhoid cases, or who are 

 convalescing from, or actually suffering from, the infection them- 

 selves. 



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 has called attention to the fact that oysters 

 grown in waters close to sewage discharges may be the means of typhoid 

 transmission. An epidemic occurring at Wesleyan University was at- 

 tributed by him to this cause. Experiments by Foote ^ have actually 

 demonstrated that typhoid bacilli may be found alive within oysters 

 for three weeks or more after they have disappeared from the sur- 

 rounding water. 



Indirect contamination of food and water by the intermediation of 

 flies and other insects has been emphasized by Veeder ' as one of the 

 methods of typhoid transmission. This observer called attention to 

 the fact that in camps during the Spanish-American War flies in large 

 numbers traveled to and fro between the sinks and the cook-tents, and 

 it is not unlikely that at least some of the typhoid fever occurring at 

 that time may have been caused in this way. 



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 * 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 



» Conn, Med. Record, Dec, 1894. ^ Foote, Med. News, 1895. 



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



