532 D YSENTER K 



amoebae described are the causes of the form of dysentery 

 with which they are associated. We are still ignorant, 

 however, as to their life-history outside the body, and the 

 modes by which infection is produced. Further, in any 

 case where they act as the primary agent, secondary in- 

 flammatory changes in the intestine may be produced by 

 the action of various bacteria. 



Varieties of Dysentery. We have already pointed out 

 that all dysenteric conditions are not of the same nature, 

 and that in certain forms amoebae are not present. Ogata, 

 for example, investigated an extensive epidemic in Japan 

 without detecting amoebae. He found, however, in sections 

 of the affected tissues enormous numbers of small bacilli 

 about the same thickness as the tubercle bacillus, but very 

 much shorter. These bacilli were sometimes found in a 

 practically pure condition. They were actively motile and 

 could be stained by Gram's method. He also obtained 

 pure cultures from various cases and tested their patho- 

 genic effects. They grew well on gelatine at the ordinary 

 temperature producing liquefaction, the growth somewhat 

 resembling that of the cholera spirillum. By injection into 

 cats and guinea-pigs, as well as by feeding them, this 

 organism was found to have distinct pathogenic effects ; 

 these were chiefly confined to the large intestine, haemor- 

 rhagic inflammation and ulceration being produced. 



Kruse and Pasquale conclude that so far as our present 

 knowledge of the etiology of dysentery goes, there are 

 several varieties which may be arranged as follows : First, 

 the amoebic or tropical dysentery, having the characters as 

 above described ; second, the various diphtheritic and 

 catarrhal forms without amoebae, possibly produced by 

 bacteria of different kinds, but the nature of which has not 

 been fully investigated ; third, the Japanese form of dysentery 

 as investigated by Ogata. 



Methods of Examination. The faeces in a case of sus- 

 pected dysentery ought to be examined microscopically 

 as soon as possible after being passed, as the amcebae dis- 

 appear rapidly, especially when the reaction becomes acid. 



