THE BACILLUS OF TYPHOID FEVER. 369 



at the conclusion that when the typhoid bacillus is cultivated for a 

 long time in media which are more and more largely diluted with 

 water, it acquires an increased ability to survive in river water. 



A predisposition to typhoid infection is established by various 

 -depressing agencies, such as inanition, overwork, mental worry, in- 

 sanitary surroundings, etc. And there is considerable evidence in 

 support of the supposition that exposure to the offensive gases 

 given off from ill-ventilated sewers constitutes a predisposition to 

 the disease. 



Experiments made by Alessi (1894), in the Hygienic Institute 

 of the University of Rome, give support to this view. The ex- 

 periments were made upon rats, guinea-pigs, and rabbits. The 

 rats were confined in a close cage with perforated bottom, which was 

 placed over the opening of a privy ; the guinea-pigs and rabbits in 

 similar cages having a receptacle below in which their own excreta 

 was allowed to accumulate. The animals which breathed an atmo- 

 sphere vitiated in this way lost, after a time, their usual activity and 

 became emaciated, although they continued to eat greedily. When 

 these animals were inoculated with a small quantity of a culture of 

 the typhoid bacillus (0.25 to 0.5 cubic centimetre) they died within 

 from twelve to thirty-six hours. The same amount of the typhoid 

 culture injected into control animals produced no injurious effect. In 

 the animals which succumbed to typhoid infection there was found a 

 hemorrhagic enteritis, increase in volume of Peyer's glands and of the 

 spleen, and typhoid bacilli in the blood, liver, and spleen. The char- 

 acteristic appearances of typhoid infection were more pronounced in 

 the rabbits and guinea-pigs than in rats. Similar experiments with 

 Bacillus coli communis gave similar results. The time required to 

 induce this predisposition for typhoid infection was from five to 

 seventy-two days for the rats, seven to fifty-eight for the guinea- 

 pigs, and three to eighteen for the rabbits. Alessi found that the 

 susceptibility to infection diminished after a certain time, and sug- 

 gests that in a similar way man may become habituated to breathing 

 an atmosphere containing sewer gases. 



Pus- Product ion by Typhoid Bacilli. The recent literature re- 

 lating to the typhoid bacillus includes many observations as to its 

 presence in accumulations of pus in various parts of the body often 

 in a pure culture. It has been found in a considerable number of 

 cases of periostitis secondary to typhoid fever, in purulent syno- 

 vitis, and in abscesses in various parts of the body. 



Dmochowski and Janowski (1895), as the result of a review of the 

 literature and a painstaking experimental research, arrive at the con- 

 clusion that ev^n in abscesses, occurring in typhoid fever cases, in 

 which only the pus cocci are found, it is probable that the typhoid 



% <. A 



