Bacillary Dysentery 691 



Glycerin agar-agar seems less well adapted to their growth than 

 plain agar-agar. Blood-serum is not a suitable medium. 



Litmus Milk. — Milk is not coagulated. As the growth progresses 

 there is slight primary acidity, which later gives place to an increas- 

 ing alkalinity. 



Potato. — Upon boiled potato the young growth resembles that 

 of the typhoid bacillus, but after twenty-four hours it becomes 

 yellowish brown, and at the end of a week forms a thick, brownish- 

 pink pellicle. 



Bouillon. — In bouillon the bacillus grows well, clouding the 

 liquid. No pellicle forms on the surface. 



Metabolic Products. — The organism does not form indol, does 

 not ferment dextrose, lactose, saccharose, or other carbohydrates. 

 Acids are produced in moderate quantiteis after twenty-four hours 

 in dextrose media. Milk is not coagulated. Gelatin and blood- 

 serum are not liquefied. 



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

 prepared by making massive agar-agar cultures in Kitasato flasks 

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

 bacillary mass with a very small quantity of sterile salt solution, 

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

 minutes, permitting the rich suspension to autolyze for three 

 day?. The toxins may be precipitated from the sodium chlorid 

 solution by ammonium sulphate, which is removed by dialysis and 

 the residuum dried in vacuo. Of the powder thus obtained 0.0025- 

 0.005 gJ^- is fatal, when intravenously administered to a rabbit. The 

 most interesting effect of the toxin is seen when rabbits are given 

 large enough doses to induce death in about twelve hours. In the 

 course of a few hours they develop diarrhea and when examined 

 postmortem are found to have, among other lesions, an enterocolitis 

 of varying severity, sometimes with the formation of a pseudomem- 

 brane upon the mucosa of the intestine. Small increasing doses of 

 the toxin, administered in succession, produce immunity against its 

 effects, but the antibody thus formed is not antagonistic to the 

 living baciUi. 



Vital Resistance. — The thermal death-point is 65°C. maintained 

 for fifteen 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; 

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

 quantity of Shiga bacilli introduced into the stomach with an 



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

 Aout, 1904, p. 634. 



