36 4 THE BACILLUS OF TYPHOID FEVER. 



Numerous experiments have been made to determine the amounts 

 of various germicidal agents required to destroy the vitality of this 

 bacillus, and the action of antiseptics in restraining its development. 

 For the results of these experiments the reader is referred to the 

 sections in Part Second relating to the action of antiseptics and disin- 

 fectants. 



Pathogenesis. The very numerous experiments which have been 

 made on the lower animals have not been successful in producing in 

 any one of them a typical typhoid process. Nor is this surprising, 

 in view of the fact that, so far as is known, no one of them is liable to 

 contract the disease, as man does, by the use of infected food or 

 water. 



The experiments of Frankel and Simmonds show that when con- 

 siderable quantities of a pure culture of this bacillus are injected into 



Fia 118 Section through wall of intestine, showing invasion by typhoid bacilli. X 950. 

 (Baumgarten.) 



the circulation of rabbits through the ear vein, or into the peritoneal 

 cavity of mice, a certain proportion of the' inoculated animals die, 

 usually within forty-eight hours, and that the bacillus may be re- 

 covered from the various organs, although it is not present in the 

 blood. But death does not always occur from intravenous injections, 

 and subcutaneous or intraperitoneal injections in rabbits are usually 

 without result. Subcutaneous injections in mice proved to be fatal in 

 ten cases out of sixteen inoculated by A. Frankel. Seitz, by following 

 Koch's method i.e., by rendering the contents of the stomach alka- 

 line, and arresting intestinal peristalsis by the administration of 

 opium obtained a fatal result, in a majority of the guinea-pigs experi- 

 mented upon, from the introduction of ten cubic centimetres of a 

 bouillon culture into the stomach through a pharyngeal catheter. 

 We may remark, with reference to these results, that while they show 

 that cultures of the typhoid bacillus have a certain pathogenic power, 



