TYPHOID FEVER 97 



toxin is contained within the bacterial cells and when all these are 

 removed by filtration, the filtrate is without harmful efiect. These 

 investigations indicate that the toxin is absorbed from the alimentary 

 canal of young animals, while it is not taken up from the digestive 

 tract of adults. Both the gastric and pancreatic juices were found 

 to be without effect upon these bacilli, and the filtrates obtained after 

 digestion of the bacterial cells in these fluids were without poisonous 

 action. Inasmuch as no bacteria were found in the blood of any of 

 the internal organs, we must conclude that the germ cells undergo a 

 process of disintegration or digestion, while being absorbed through 

 the intestinal walls. Boiling milk cultures of this toxicogenic, pep- 

 tonizing bacillus destroys their virulence but it must not be inferred 

 from this that all milk containing toxicogenic germs is rendered 

 harmless by heat. The colon bacillus is frequently found in market 

 milk and it is altogether likely that this germ plays an important 

 r6le in the causation of the summer diarrhoeas of infancy and, as 

 we shall see later, the colon toxin resists very high temperatures. 



Typhoid Fever. — The specific character of the bacillus discovered 

 by Eberth in 1880 has been abundantly demonstrated by subsequent 

 bacteriological research, and there is no doubt that this microorgan- 

 ism is the cause of typhoid fever. In 1885, Brieger obtained from 

 pure cultures of the Eberth bacillus a poisonous ptomain, which pro- 

 duced in guinea-pigs a slight flow of saliva, frequency of respiration, 

 dilatation of the pupils, profuse diarrhoea, paralysis, and death within 

 from twenty-four to forty-eight hours. Post mortem examination 

 showed the heart in systole, the lungs hyperemic, and the intestines 

 contracted and pale. At first Brieger was inclined to regard this as 

 the specific poison of typhoid fever, and named it typhotoxin, but 

 more extended investigation has shown that this substance cannot be 

 regarded as the essential toxin of the Eberth bacillus. In their re- 

 searches upon the toxalbumins, Brieger and Frankel found in cul- 

 tures of the typhoid bacillus a proteid which caused death in rabbits 

 after from eight to ten days. This substance undoubtedly contained 

 the typhoid toxin but was by no means a pure preparation of this 

 substance. 



Pfeiffer has demonstrated that typhotoxin is contained in the bac- 

 terial cells and he has shown that 4 mg. of the dried cells for each 

 100 grams of body weight suffice to Mil guinea-pigs. With this 

 poison animals can be rendered immune to the Eberth bacillus, and 

 the blood of such immune animals contains a slightly active anti- 

 toxin, which, however, has not proved of value in the treatment of 

 the disease. 



In 1889, Vaughan isolated from mixed cultures from typhoid 

 stools a base, forming crystalline salts and capable of inducing in 

 cats and dogs a marked elevation of temperature accompanied by 

 7 



