Bacillary Dysentery 651 



Acids are produced in moderate quantities after twenty-four hours. 

 Milk is not coagulated. Gelatin is not liquefied. 



Toxins, chiefly endotoxins, are produced. They may best be 

 prepared by making massive agar-agar cultures in Kitasato flasks 

 or fiat-sided bottles, and after growth is complete washing off the 

 bacillary mass with a very small quantity of sterile salt solu- 

 tion, and after killing the bacilli by exposure to 6o°C. for fifteen to 

 thirty minutes, permitting the rich suspension to autolyze for 

 three days. The toxins may be precipitated from the sodium 

 chlorid solution by ammonium sulphate. 



Vital Resistance. — The thermal death-point is 68°C. maintained 

 for twenty minutes. It grows slowly at ordinary temperatures, 

 rapidly at the temperature of the body. 



Pathogenesis. — Shiga and Flexner found that infection of young 

 cats and dogs could be effected by bacilli introduced into the stom- 

 ach, and that lesions suggestive of human dysentery were present in 

 the intestines. Kazarinow* found that when guinea-pigs and 

 young rabbits were narcotized with opium, the gastric contents 

 alkahnized with 10 cc. of a 10 per cent. NaOH solution, and a 

 quantity of Shiga bacilli introduced into the stomach with an 

 esophageal bougie, it was possible to bring about diarrhea and 

 death with lesions similar to those described by Vaillard and Dopter. 



In these experiments it was found that rapid passage through 

 animals greatly increased the virulence of the bacilli, and it was 

 also observed that though 0.0005 ^c. of a virulent culture intro- 

 duced into the peritoneal cavity would cause fatal infection, to 

 produce infection by the mouth as above stated required the en- 

 tire mass of organisms grown in five whole culture-tubes. 



The virulent organisms are infectious for guinea-pigs and other 

 laboratory animals, and cause fatal generalized infection without 

 intestinal lesions. 



Lesions. — The lesions found in human dysentery are usually 

 fairly destructive. They consist of a severe catarrhal and pseudo- 

 membranous, colitis, which later passes into a stage of marked 

 ulceration. There is great thickening of the submucosa and the 

 whole of the intestinal lining is corrugated. For the most part the 

 ulcerations are more superficial than those of the amebic dysentery, 

 and the edges of the ulcerations show less tumefaction and less 

 undermining. Abscess of the liver does not occur in bacillary 

 dysentery. 



Diagnosis. — The blood-serum of those suffering from epidemic 

 dysentery or from those recently recovered from it causes a well- 

 marked agglutinative reaction. This agglutination was first care- 

 fully studied by Flexner, and is peculiar in that the serums pre- 

 pared from the different varieties of the bacillus, while they exert 



* "Archiv. f. Hyg.," Bd. L, Heft i, p. 66; see also "Bull, de I'lnst. Past.," 15 

 Aout, 1904, p. 634. 



