350 BACILLARY DYSENTERY. 



amoebic and non-amoebic forms have been distinguished. Of 

 the latter bacteria have been believed to be the causal agents, 

 and an organism described by Shiga in 1898 has almost been 

 established as the cause of a large proportion of cases. Shiga's 

 observations were made in Japan, and the confirmatory results 

 obtained by Kruse in Germany, by Flexner and by Strong and 

 Harvie in the Philippine Islands, and more recently by Vedder 

 and Duval in the United States, tend to show that the distribu- 

 tion of the specific organism is world-wide. The last-mentioned 

 observers also compared the bacteria obtained from these differ- 

 ent localities and found them to be identical. Further interest 

 is attached to the role played by this organism by the researches 

 of Duval and Bassett, who seemingly have isolated the bacillus 

 from the faeces in forty-two cases of summer diarrhoea in infants, 

 and from scrapings of the intestinal mucosa at autopsy, and in one 

 case from the mesenteric glands and liver. Spronck working in 

 Holland confirms the work of Duval and Bassett by similar results 

 in three cases of the same disease. The evidence for the rela- 

 tionship of the organism to the disease consists chiefly in the 

 apparently constant presence of the organism in the dejecta in 

 this class of dysentery, the agglutination of this organism by the 



serum of patients suffering 



, from the disease, and in 



the production of a cura- 

 tive serum through the 

 immunising of sheep and 

 asses with pure cultures of 



I the bacillus. The relation 



of amoebae to dysentery 

 will be discussed in the 

 X, Appendix. 



Bacillus dysenteriae 

 (Shiga). Morphological 

 Characters. This bacillus 

 morphologically closely 



FIG. n8A. B. dysenteriae; from an agar cul- resembles the typhoid 

 ture 48 hours old. Stained with aniline-gentian- KaHlliis but is On the 



violet, x looo. 



whole somewhat plumper, 



and filamentous forms are comparatively rare (Fig. n8A). 

 Involution forms sometimes occur, specially in glucose agar. 



