55 Typhoid Fever 



Pfeiffer and Kolle * found toxic substance in the 

 bodies of the bacilli only. It was not, like the toxins of 

 diphtheria and tetanus, dissolved in the culture medium. 

 This was an obstacle to the immunization experiments of 

 both Pfeiffer and Kolle and Loffler and Abel,f for the only 

 method of immunizing animals was to make massive agar- 

 agar cultures, scrape the bacilli from the surface, and dis- 

 tribute them through an indifferent fluid before injecting 

 them into animals. 



If the bacilli grown upon ordinary culture media are 

 several times washed in distilled water, and then allowed 

 to macerate in normal salt solution, autolysis takes place 

 and a toxin is liberated, showing that the toxin is intracel- 

 lular. Macfadyen and Rowland t liberated an intracellular 

 toxin from cultures of the typhoid bacilli by freezing them 

 with liquid air and grinding them in an agate mortar. Ani- 

 mals immunized with this poison produced an anti-serum 

 active against it, but useless against infection with typhoid 

 bacilli. Wright, of Netley, observes that Macfadyen's 

 method of securing this intracellular toxin was unneces- 

 sarily cumbersome, as the body juices of animals injected 

 with dead cultures of the bacilli dissolve them at once and 

 thus liberate the same toxic product. 



Invasion of the Body. The typhoid bacillus probably, 

 in the great majority of cases, enters the alimentary tract 

 with infected food and water, but may at times be in- 

 haled (Klemperer and Levy). 



Pathogenesis. It is almost universally believed that 

 infection by the typhoid bacillus takes place through 

 polluted drinking-water, and the epidemiology of the dis- 

 ease seems to point unmistakably in that direction. In 

 favor of it as the almost invariable result of purifying the 

 drinking-water is diminution of the number of cases or 

 disappearance of the disease. Opposed to it are the almost 

 invariable failure of bacteriologists to discover the typhoid 

 bacillus in waters thought to be extremely dangerous, and 

 our knowledge of the rapidity with which the typhoid 

 bacillus becomes extinguished in waters containing other 



* "Deutsche med. Wochenschrift," Nov. 12, 1896. 

 f "Centralbl. f. Bakt. u. Parasitenk.," Jan. 23, 1896, Bd. xix, No. 

 23, P- Si- 



J "Brit. Med. Jour.," 1903. 

 Ibid., April 4, 1903, I, p. 786. 





