42 HUMAN INTESTINAL PROTOZOA IN THE NEAR EAST 



true that a certain type of nucleus is more commonly found in 

 E. histolytica and another type in E. coli, and that in one it is 

 more often visible in the living amoeba than in the other, but here 

 again it is exceedingly doubtful if such details of structure can be 

 employed as a basis of diagnosis. Size is of no value whatever in 

 the differentiation of unencysted forms of E. coli and E. histolytica. 

 It is a very easy matter to state that a certain type of nucleus 

 belongs to E. histolytica and another type to E. coli, and dog- 

 matically to diagnose amoebae accordingly, but is there sufficient 

 evidence that the nuclei maintain their characters so consistently 

 as to justify one in making dogmatic assertions on this basis and 

 to condemn patients to courses of emetin and other treatment 

 accordingly ? 



In examining stools one often sees highly refractile, distinctly 

 green amoebae with or without vacuolation. As a rule no nucleus 

 can be seen in them and there is either no movement at all or very 

 sluggish change of shape. They may be perfectly round and it 

 may be difficult on account of the refractile edge to be sure that the 

 amoebae are not encysted. In other cases there may be numerous 

 short conical elevations or irregularities over the whole surface 

 which are hardly pseudopodia and which remind one most of the 

 short pseudopodia of Amoeba verrucosa ; while at other times there 

 may be several rather long, lobose, sometimes branched pseudo- 

 podia which move very sluggishly. Amoebae of this type are met 

 with both in undoubtedly pure E. coli infections and in the 

 " carrier " stage of E. histolytica infections. It is not only quite 

 impossible to recognize whether these are E. coli or E. histolytica, 

 but it is often exceedingly difficult to tell whether they are amoebae 

 at all, especially when they occur in association with the large 

 cells so often seen in the bacillary dysentery exudate. Again, 

 E. histolytica in acute cases may be very difficult to identify. It 

 often, of course, has the characteristic structure of distinct ectoplasm 

 and granular or vacuolated endoplasm, but at other times it may be 

 nothing more than a clear hyaline apparently structureless mass, 

 or a mass of such hyaline material filled with numerous vacuoles. 

 We can recollect, having watched a clear hyaline body for some time, 

 wondering the while whether it was a tissue cell on the way to 

 degeneration or an amoeba, when suddenly there burst from its side 

 a large pseudopodium and the amoeba commenced that series of 

 active movements which one practically never sees except in the 

 case of E. histolytica. This particular case had also amoebae with 

 included red blood corpuscles. We mention these points in order 



