PART III. TREATMENT 115 



at first sight appear. A case with acute dysentery is passing large 

 entamcebae quite unlike the encysting generation of small amcebse, 

 and if etnetin is to cause the amoebae to encyst we must suppose 

 that its first effect is to make the large amoebae divide rapidly to 

 produce small forms, and that these must take on the characters of 

 the pre-encysting " minuta " forms of E. histolytica. This is quite 

 another matter than the supposed quick secretion of a capsule round 

 an amoeba, because it is being irritated by small doses of emetin. 



We have already seen that the natural course of an amoebic 

 infection is that of the carrier case, and that in a certain percentage 

 of these where the ulceration of the gut is extensive attacks of 

 dysentery manifest themselves from time to time, while, between 

 the attacks, the condition of the carrier is reverted to. In whatever 

 way a person becomes infected with E. histolytica, whether by an 

 initial attack of amoebic dysentery or not, the natural tendency is 

 towards the development of the carrier condition. This being the 

 case it is manifestly impossible to regard inadequate emetin treat- 

 ment as a factor which increases the number of carrier cases, for 

 these cases if left untreated would have become carriers in any 

 case. Moreover, the supposed inadequate treatment would probably 

 have cured a few cases at least, so must have reduced the total 

 number of possible carriers. 



It is quite possible that when the " encysting " or "minuta" 

 generation of E. histolytica is present in the intestine some adverse 

 influence might suddenly cause an encystment of numbers of these, 

 but before we can decide this point we must understand the normal 

 course of such infections, judged by the appearance in the stools. 

 A person who is in the carrier condition passes both cysts of 

 E. histolytica and minuta forms of amoebae, but these are not passed 

 regularly. On some days cysts alone are passed, while on others 

 the amoebaB are most numerous or alone present. Much depends 

 on the consistency of the stool. In some of the carrier cases treated 

 by us the emetin course was commenced only when cysts were 

 being passed and the immediate effect has appeared to be the dis- 

 appearance of the cyst with the passage of free amoebae. On the 

 other hand the reverse has occurred, while generally in the cases 

 of pure E. histolytica infection the cysts have tended to disappear 

 from the stool before the amoebae. The results we have obtained 

 do not afford any evidence in favour of the view that the emetin 

 causes the amoebae in the gut to encyst. Nor have we been able to 

 obtain any evidence that the emetin treatment causes any particular 

 form of cyst to appear in the stool. In the examinations for carrier 



