PART II. CHARACTERS AND DIAGNOSIS 41 



PART II.* 



THE CHARACTERS AND DIAGNOSIS OF THE VARIOUS INTESTINAL 

 PROTOZOA OP MAN IN EGYPT WITH A DESCRIPTION OF 

 THREE NEW FORMS. 



This section of the report has to do mainly with the morphology 

 of the human intestinal Protozoa. We have not attempted to give 

 a complete description of these. This has already been done fairly 

 completely in other papers, but we have noted some important new 

 points and attention is called to these in the various sections below. 

 Finally, we have described three new parasites two flagellates and 

 an amoeba which have not been previously found in the human 

 intestine. 



(1) Characters and Diagnosis of Unencysted Entamceba 

 histolytica. 



As regards the morphology of this amoeba we have very little to 

 add to what has already been so often described. We are con- 

 vinced that its identification, apart from the presence of included 

 red blood corpuscles, presents the greatest difficulties even for the 

 expert and trained observer. It is true that a certain type of 

 amoeba with refractile ectoplasm, indistinct nucleus and active 

 movement is most likely E. histolytica, but very often the amoeba; 

 take on quite other appearances and become practically indis- 

 tinguishable from certain forms of E. coll. They sometimes have 

 perfectly distinct nuclei, they may be very sluggish in their move- 

 ments, they may show little or no distinction between ectoplasm 

 and endoplasm, and they may vary very greatly in the degree of 

 their vacuolation and refractibility. Furthermore, we have seen 

 amoebae which are undoubtedly E. coli moving with an activity 

 which is comparable only with that of E. histolytica. Still, as a 

 rule, an amoeba is E. histolytica if it is moving with an active 

 streaming motion and throwing out pseudopodia, sometimes after 

 several minutes of perfect quiescence, with that peculiarly ex- 

 plosive suddenness which cannot be appreciated unless seen. No 

 amount of description, as James points out, can give an accurate 

 mental picture of this remarkable amoeboid activity. It is probably 



* Reprinted from the Journal of the Royal Arm;/ Medical Corps, February 

 March, 1917. 



