Bacillus Dysenteriae 527 



border is observed about each colony, and the bacilli of 

 which it is composed cease to stain evenly, presenting in- 

 volution forms. 



Glycerin agar-agar seems less well adapted to their growth 

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

 medium. 



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 surfaced 



Metabolic Products. The organism does not form in- 

 dol, does not ferment sugar, and in gelatin and agar-agar 

 containing sugars no gas is evolved. Acids are produced in 

 moderate quantities after twenty-four hours. Milk is not 

 coagulated. 



Vital Resistance. Its thermal death-point is 68 C. 

 maintained for twenty minutes. It grows slowly at ordi- 

 nary temperatures, rapidly at the temperature of the body. 

 The culture media should be alkaline. 



Pathogenesis. Bacillus dysenteriae was found by Shiga 

 in all the cases of epidemic dysentery studied in Japan, 

 by Flexner in the epidemic dysentery of the Philippine 

 Islands, and by Vedder and Duval * in the epidemic and 

 sporadic dysentery of the United States. Duval and Bas- 

 settf and Martha WollsteinJ found Bacillus dysenteriae in 

 cases of the summer diarrheas of infants, especially when 

 such diarrheas were epidemic. 



Diagnosis. Kazarinow found that when guinea-pigs and 

 young rabbits were narcotized with opium, the gastric con- 

 tents alkalinized with loc.c. of a 10 percent. 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 



*" Journal of Experimental Medicine," vol. vi, No. 2, 1902; and 

 "American Medicine," 1902. 



t" American Medicine," Sept. 13, 1902, vol. iv, No. 11, p. 417. 



|" Jour. Med. Research," x, p. 11, 1904. 



"Archiv. f. Hyg.," Bd. L, Heft 1, p. 66; see also "Bull, de 1'Inst. 

 Past.," ISAout, 1904, p. 634. 



