BACILLI OF THE COLON-TYPHOID-DYSENTERY GROUP 701 



ordinary anilin dyes it stains easily, showing a tendency to stain with slightly 

 greater intensity at the ends. The organism is an aerobe and facultative anaer- 

 obe. Although described at first by Shiga as being motile, its motility has not 

 been satisfactorily proven, and most observers agree in denying the presence of 

 flagelte, and affirming the complete absence of motility. 



On cigar the colonies are not characteristic, resembling those of the typhoid 

 bacillus. 



On gelatin, the colonies appear very much like typhoid colonies and the gela- 

 tin is not liquefied. On potato, the growth, like that of typhoid, is at first not 

 visible, but after about a week turns reddish brown. 



In broth, there is clouding, with moderate deposits after some days. No 

 pellicle is formed. 



Milk is not coagulated. Litmus milk shows a slight primary acidity, later 

 again becoming alkaline and taking on a progressively deeper blue color. 



Indol is not formed. 



No gas is formed in media containing dextrose, lactose, saccharose, or other 

 carbohydrate. 



While not delicately susceptible to reaction, the bacillus prefers slightly 

 alkaline media. 



Shiga differentiated his organism from the typhoid bacillus chiefly by sup- 

 posed differences in colony characters and by the agglutination reaction. 



Following the work of Shiga, a large number of investigators turned 

 their attention to the subject of dysentery, with the result that many 

 new forms were discovered and at first a considerable amount of con- 

 fusion prevailed. 



Flexner 2 in 1899 investigated dysentery in the Philippines, and 

 isolated a bacillus which, he considered, corresponded to Shiga's 

 organism. 



Strong and Musgrave 3 in 1900 described a bacillus isolated from 

 dysentery cases in the Philippines which was essentially like that of 

 Flexner. 



Nearly simultaneously with the papers of Flexner and of Strong and 

 Musgrave, Kruse 4 published investigations of an epidemic of dysentery 

 occurring in Germany. His observations were of the greatest impor- 

 tance and largely formed the starting point of the further advances 

 which have been made in the etiology of dysentery. 



Kruse's organism was described as forming colonies on gelatin and 

 agar, practically like those of Bacillus typhosus. Like this bacillus, no 

 gas was formed from grape sugar, and the growth in milk and on potato, 



2 Flexner, Phila. Med. Jour., vi, 1900, and Bull. Johns Hopkins Hosp., xi, 1900. 



3 Strong and Musgrave, Report Surg. Gen. of Army, Washington, 1900. 



4 Kruse, Deut. med. Woch. ; xxvi, 1900. 



