312 PATHOGENIC BACTERIA IN MILK 



detectable in cases of clinical typhoid fever, and does not produce 

 the specific disease in animals. 



The evidence that Eberth's bacillus is the cause of typhoid fever 

 consists in the main of three parts. In the first place, the bacillus 

 is found, with almost invariable regularity, in the spleen of persons 

 dying of typhoid fever, when an adequate bacteriological examina- 

 tion is made. Secondly, Eberth's bacillus elaborates specific toxins. 

 Thirdly, the blood serum of individuals suffering from typhoid fever 

 has a specific agglutinative action upon the Eberth bacillus, similar 

 to that observed in the blood serum of animals, rendered immune 

 to this germ (compare also Pfeiffer's reaction).^ And whilst there 

 is no evidence to suppose that animals, including the cow, suffer 

 from typhoid fever, as the disease occurs in man, there is evidence 

 to show that under certain conditions, a disease, not unlike enteric 

 fever, can be produced by inoculation of the B. typhosus into guinea- 

 pigs, mice, rabbits, etc. (Frankel and Simmonds). Klein has also 

 recently demonstrated by inoculation, that the bacillus is able to 

 multiply and develop in the lymph glands of the calf. 



For all practical purposes, therefore, the B. typhosus of Eberth is 

 now generally accepted as the causal agent in typhoid fever. It lives 

 in milk and in sewage, but in both only for a comparatively brief 

 period, unless the medium is freshly diluted. The reason for this is, 

 of course, the enormous competition created by the vast numbers of 

 saprophytic organisms present both in milk and in sewage. In the 

 struggle which ensues the B. typhosus succumbs. It is not unlikely 

 that the bacillus is widely distributed in nature, and yet it is only 

 under certain conditions and circumstances that it gains access to 

 the human body in such. numbers, or in such a degree of virulence, 

 as to create disease. It certainly has powers of rapid multiplication, 

 and in a few hours, some scores of bacilli introduced into a water 

 supply will have reached many millions. Great dilution to which it 

 may be subjected has no ill effect upon its potency. Lastly, certain 

 organisms often associated with it are antagonistic to its growth, 

 whilst others are favourable and appear to increase its virulence. 



Therefore accepting Eberth's bacillus provisionally as the etio- 

 logical agent in typhoid, we find ourselves at once in possession of 

 an agent of extreme variability, both as regards its presence in milk 

 and its virulence in the human body. It may be this factor of varia- 



' Compare also sensibility to agglutination of certain varieties of B. colt 

 isolated from typhoid stools and note the value such a phenomenon may be 

 in the detection of typhoid dejecta in water or milk. See Jour, of Hyg., 1902, 

 p. 213 (W. H. Horrocks). 



