BACILLUS TYPHI ABDOMINALIS 173 



small amount of phenol. Plate cultures are then instituted with the 

 carbolized water after the method of Eisner. 



In this examination it is apparent that to get positive results large 

 quantities of the water may have to be examined, and this is best done 

 thus : An alkaline sterilized solution made with peptone and common 

 salt, containing 1 gramme of each in a given volume, is taken. With 

 this you mix 100 c.c. of the carbolized water supply, and place in sterile 

 Erlenmeyer flasks, and put in the incubator for eighteen to twenty- 

 four hours. Under these conditions the growth of any typhoid bacilli is 

 allowed to go on practically without competition, and the bulk of the 

 mixture gives greater chances of their appearing in plate cultures. 



This system enables one to separate out chiefly typhoid and pseudo- 

 typhoid forms as well as coli commune, which is really more resistant to 

 phenol than is typhoid itself, and further researches must be instituted 

 with the individual colonies to get absolute differentiation. 



Pathogenesis. When some virulent culture is introduced in 

 mice, guinea-pigs, rabbits, and goats, death occurs with the following 

 symptoms : Spasms, falling temperature, and diarrhoea. By sub- 

 cutaneous injection large quantities of the culture are necessary, but by 

 intraperitoneal and intravenous methods a small quantity is sufficient. 

 Experimental results in the lower animals show that in most cases 

 death occurs without the appearance of typical pathological changes, 

 the fatal result in most cases being due to toxic rather than to 

 infective action of the virus. Cygnaeus introduced typhoid bacilli 

 into the tissues of dogs, rabbits, and mice, and produced changes in 

 the small intestines, histologically and macroscopically analogous to 

 those found in the human subject. Abbot obtained only one positive 

 result out of a large number of experiments, producing an ulcer in the 

 ileum of a rabbit, macro- and microscopically identical with that found 

 in man. Cultivations were obtained from the spleen, and the typical 

 bacilli demonstrated in characteristic clumps in sections of the same. 

 Sanarelli found that rabbits, guinea-pigs, and mice were rendered 

 susceptible to infection when first inoculated with the products of the 

 growth of certain saprophytes, Proteus vulgaris, Bacillus prodigiosus, 

 and Bacillus coli communis, and when subsequently fresh cultures of 

 the typhoid bacillus were introduced intravenously or into the 

 peritoneal cavity, death resulted in twelve to forty-eight hours, with 

 well-marked pathological changes in the digestive tract, especially in 

 the small intestines. The infection is general in those cases, and the 

 bacilli can be recovered from the blood and internal organs. Sanarelli 

 considers that the toxic condition produced by the absorption of the 

 products of the saprophytes may be analogous to a similar condition 



