﻿242 The Philippine Journal of Science 1914 



For example, as is well known, staphylococci, streptococci, 

 the colon bacilli, and other organisms frequently, if not usually, 

 are found in the normal intestine, and it is a fact that under 

 certain conditions these organisms may be the responsible agents 

 in an acute colitis. Bacillus dysenterise under ordinary circum- 

 stances is found associated with, and is accepted as the cause of, 

 one type of acute cohtis. Under certain conditions of immunity 

 on the part of the host, decreased virulence of the strain of the 

 organism may occur, and under other circumstances which 

 probably are not explainable with our present knowledge this 

 bacillus may persist for long periods of time in a perfectly 

 healthy intestine — the bacillus "carrier." However, let this 

 protected balance be broken in any of its links as by (a) de- 

 creased immunity on the part of the host, (6) increased virulence 

 or volume of infecting agents, or (c) altered environmental in- 

 fluence, and a severe colitis results. 



All of these influences are important considerations in the 

 spread of the infection, and in communities where public health 

 and personal hygiene are not the most efficient it is largely by 

 establishing balanced combinations of these conditions that epi- 

 demics are controlled. 



HISTORICAL 



Shiga ^ described a bacillus occurring in an epidemic of dysen- 

 tery in Japan, and concluded that this organism was the cause 

 of the disease. Flexner^ described a very similar bacillus occur- 

 ring in an epidemic of dysentery among American soldiers in 

 the Philippine Islands. Strong and Musgrave^ isolated a very 

 similar organism from cases of acute dysentery in Manila, and 

 proved its etiologic relationship to the disease by experiments 

 on animals and in one case on man. 



Kruse* described a dysentery bacillus similar to Shiga's as 

 being the positive agent in an epidemic of dysentery in Germany. 



Careful laboratory workers very soon began to notice slight 

 cultural differences between the various strains of the organisms 

 isolated by the diflferent workers, and various classifications of 

 the group have been made as a result of studies from the different 

 laboratories. 



'Centralbl. f. Bakt. (1898), 23, 599. 



'Bull. Johns Hopkins Hosp. (1900), 11, 231, and Centralbl. f. Bakt. 

 (1900), 28, 626. 



* Rep. Surgeon-General U. S. Army (1900), 251. 

 *Deut8ch. med. Wochenschr. (1900), 26, 637. 



