PART III. TREATMENT 123 



passing produced a fatal dysentery in two kittens. It must be 

 remembered that Healy had a long history of previous dysentery 

 while Carr had none, and it is probably in this direction that an 

 explanation is to be sought. Presumably the degree of involvement 

 of the large intestine was greater and of much longer standing in 

 Healy than in Carr, and in his case it was 'probably much more 

 difficult for the emetin to gain access to all the amoeba', many of 

 which would escape in localities such as the necrotic pieces of 

 tissue and the base of old ulcers where there was little or only a 

 poor circulation. 



(k) When do Relapses occur ? In our series of observations we 

 have taken as a period of control one month after treatment has 

 been completed. The majority of our cases have been controlled 

 beyond this period, during which the stools have been examined as 

 a rule on every alternate day. In this way we have been able to 

 detect a relapse as soon as it has occurred. Where relapse has 

 occurred after treatment this has taken place in under twenty days, 

 except in three cases, two of which were carriers treated by injec- 

 tions of one grain of emetin, and one an acute case. In every 

 instance the relapse was judged, as was the diagnosis in the first 

 place, by the appearance of cysts of E. histolytica or amoebae with 

 included red blood corpuscles. It seems evident, therefore, that a 

 control of one month after treatment is quite sufficient to ensure 

 that a cure has taken place. Many of our cases have been subjected 

 to an even longer control. 



As regards the acute cases it has been pointed out above that 

 the diagnosis of these was made on the occurrence of amoebae with 

 included red blood corpuscles in a dysenteric stool and that the 

 treatment in all cases caused the rapid disappearance of symptoms, 

 though the infection might not disappear till later. When these 

 cases relapsed, and this has unfortunately happened in the majority 

 of acute cases treated by us, there is not at first a return of the 

 dysentery, but the relapse has been detected by the appearance of 

 cysts of E. histolytica in the stool. One such case (Russell) has 

 been mentioned already. The first sign of relapse was the appear- 

 ance of cysts in the stool and some time after he was readmitted 

 with acute amoebic dysentery again. In the case of Smith :;: the 

 relapses could not be judged by the appearance of cysts, for this 

 case never passed any, but by the reappearance of amoebae with 

 included red blood corpuscles. 



(I) The Effect of Previous Dysentery on the Treatment. We 



* See note on case, patje 187. 



