114 HUMAN INTESTINAL PROTOZOA IN THE NEAR EAST 



for twelve days, a course of ernetin by the mouth, and in addition, 

 irrigation of the abscess cavity with a solution of emetin. The 

 amoebae were very active and included many red blood corpuscles, 

 an observation which at once disproves the view expressed by 

 Escomel (Bull. Soc. Path. Exot., October, 1913), that^J. histolytica 

 will not ingest the red blood corpuscles of a person receiving ernetin 

 injections. On one occasion a small quantity of the pus was mixed 

 with a solution of emetin hydrochloride (one grain in one cubic 

 centimetre, or 6'5 per cent, solution), and a preparation of the 

 mixture watched under the microscope. The amoebae, instead of 

 being killed at once, moved about actively in the liquid and only 

 came finally to rest after the expiry of ten minutes. We cannot 

 state the exact strength of the emetin solution in which the amoebae 

 were moving, but it was many times in excess of the usual 1 in 

 100,000, which is claimed to kill them at once. Whether these 

 amoebae were emetin-resistant or not cannot be decided till similar 

 observations are made with amoebae from abscesses in cases which 

 have not received previous emetin treatment. The case just 

 recorded recovered in the usual way by drainage of the abscess 

 cavity, but there was no evidence to show that the various courses 

 of emetin had any influence in bringing about this fortunate 

 result. It has been claimed that emetin injections will not only 

 clear up the presuppurative hepatitis of amoebic abscess, but it will 

 sometimes cause an actual unopened abscess to disappear. The 

 case recorded above does not offer any explanation of this, though 

 it is possible that the chances of the emetin reaching the amoebae 

 in an abscess wall vary just as they do in the gut. Some abscesses 

 may have a good circulation in the surrounding tissues, so that the 

 emetin can reach the amoebae ; while in other abscesses, probably of 

 a long duration, the circulation is poor owing to the occlusion of 

 the blood-vessels by thrombosis, fibrosis or other obstruction. 



(e) Does Emetin tend to make the Amoeba encyst f It has been 

 stated that the effect of emetin, especially in inadaquate doses, is 

 to make the E. histolytica encyst and to convert an acute into a 

 carrier case. As a rule a protozoan encysts either because it 

 wishes to protect itself against some adverse influence or for repro- 

 ductive purposes, so the presence of cysts of E. histolytica is 

 looked upon as an indication of some adverse influence acting upon 

 the amoebae in the gut. It was thought, therefore, that if emetin 

 was given in insufficient doses to kill the amoebae they would tend 

 to protect themselves by encysting. The encystment of the 

 E. histolytica in the intestine is not such a simple matter as might 



