THE BACILLUS TYPHOSUS 367 



suppurative conditions (see Chapter VII.), especially in con- 

 nection with the intestine (e.g., appendicitis) and about the 

 urinary tract. In the latter, it is also responsible for catarrhal 

 conditions in the pelvis of the kidney and in the bladder, these 

 being more common in the female, and frequently presenting 

 chronic characters. As a practical point, it may be said that 

 the treatment of the latter by vaccines, especially when made 

 from the strain isolated from the lesion, has been attended with 

 marked success. The b. coli is also apparently the cause of 

 some cases of summer diarrhoea (cholera nostras), of infantile 

 diarrhoea, and of some food poisonings. 



The Pathogenicity of the B. coli and its Relation to that of the 

 Typhoid Bacillus. Intraperitoneal injection in guinea-pigs is often 

 fatal. Subcutaneous injection may result in local abscesses, and some- 

 times in death from cachexia. Sanarelli found that the b. coli isolated 

 from typhoid stools was much more virulent than when isolated from 

 the stools of healthy persons. He holds that the increase in virulence is 

 due to the effect of typhoid toxins. This increased virulence of the 

 b. coli in the typhoid intestine makes it possible that some of the patho- 

 logical changes in typhoid may be due, not to the typhoid bacillus, but 

 to the b. coli. Some of the general symptoms may be intensified by 

 the absorption of toxic products formed by it and by other organisms. 

 Differences of behaviour of the two bacilli in connection with their 

 pathological effects have been brought forward as confirmatory of the 

 fact of their being distinct species. Thus Sanarelli accustomed the 

 intestinal mucous membrane of guinea-pigs to toxins derived from an 

 old culture of the b. coli, by introducing day by day small quantities 

 of the latter into the stomach. When a relatively large dose could be 

 tolerated, it was found that the introduction in the same way of a small 

 quantity of typhoid toxin was still followed by fatal result. Pfeiffer also 

 found that while the serum of convalescents from typhoid paralysed the 

 typhoid bacilli, it had no more effect on similar numbers of b. coli than 

 the serum of healthy men. 



THE BACILLUS TYPHOSUS. 



Bacillus Typhosus. Microscopic Appearances. It is some- 

 times difficult to find the typhoid bacilli in the organs of a 

 typhoid patient. Numerous sections of different parts of a 

 spleen, for example, may be examined before a characteristic 

 group is found. The best tissues for examination are a Peyer's 

 patch where ulceration has not yet commenced or where it is 

 just commencing, the spleen, the liver, or a mesenteric gland. 

 The spleen and liver are better than the other tissues named, as 

 in the latter the presence of the b. coli is more frequent. From 

 scrapings of such solid organs dried films may be prepared and 

 stained for a few minutes in the cold by any of the strong 

 staining solutions, e.g., with carbol-thionin-blue, or with Ziehl- 



