DYSENTERY BACILLUS. 453 



bacillus. As in typhoid, early diagnosis may be 

 best accomplished by bacteriologic examination of 

 the blood. 



III. ACUTE EPIDEMIC DYSENTERY. 



In addition to amebic dysentery, we have de- 

 come familiar with an acute dysenteric infection 

 which appears epidemically in both tropical and 

 temperate climates, and prevails especially in the 

 summer months. Such epidemics occur extensively 

 in Japan, where the mortality may be 24 per cent. ; 

 in the Philippines, United States, Germany and 

 other European countries. In industrial settle- 

 ments in Germany the mortality is about 10 per 

 cent. (Kruse). The incubation period may be as 

 short as two or three days. In mild cases the pa- 

 tient may recover in from four to eight days, 

 whereas severe cases last from two to four weeks, 

 and may terminate fatally. Occasionally the in- 

 fection lasts sufficiently long to be considered 

 chronic. 



In 1898, Shiga, basing his conclusions on posi- TWO Types of 

 tive results with the agglutination test and on the 

 constant presence of the organism in the stools of 

 the infected, identified as the cause of the disease, 

 in Japan, a microbe which .is known as Bacillus 

 dysenteric?. (Shiga). Flexner, in 1900, made simi- 

 lar observations on epidemic dysentery in Manila, 

 and his organisms, or one of them, differing slight- 

 ly from that of Shiga, is called Bacillus dysenteries 

 (Flexner), or the Flexner-Harris bacillus, Harris 

 being the name of a patient from whom this 

 typical strain was cultivated. Kruse (1901) found 

 both the Shiga and Flexner types in Germany, 

 needlessly giving the name of "pseudodysentery" 

 bacilli to the latter. In this country similar organ- 



