68 HUMAN INTESTINAL PROTOZOA IN THE NEAR EAST 



refractile rods in E. histolytica as well as in E. coli. These 

 are spores of a spore-bearing bacillus (probably B. megatherium) 

 which is fairly common in faeces in Egypt (text fig. 4, page 85). 

 On another occasion most of the amoebae in an E. histolytica 

 infection had ingested larger oval refractile structures which were 

 probably yeasts. 



Does E. coli ingest Red Blood Corpuscles ? Some observers have 

 declared that E. coli may, under certain circumstances, phagocyte 

 red blood corpuscles. They have not, however, told us why the 

 entamoebse observed could not have been E. histolytica. If one 

 decides that a certain type of nucleus or cytoplasm must of neces- 

 sity belong to E. coli, then of course one is bound to declare any 

 amoeba, with such a nucleus, whether it contains red blood 

 corpuscles or not, to be E. coli. For instance, James, discussing 

 this question, states that in mixed infection of E. coli and 

 E. histolytica in stools containing blood he has found red blood 

 corpuscles in varying quantity in the interior of the pathogenic 

 organisms but rarely within coincident E. coli, and then only one 

 or two at a time. Is it not possible that in such cases the amoebae 

 were really E. histolytica which had come very near to E. coli in 

 structure? In order, therefore, to test the powers of E. coli to 

 ingest red blood corpuscles we have made some experiments about 

 which there could be no shadow of doubt. A case of pure E. coli 

 infection which had been followed continuously for nearly four 

 months was used. On two occasions when the free amoebae were 

 present in large numbers a portion of the perfectly fresh stool was 

 mixed with a quantity of finger blood of the infected individual on 

 one occasion and with the blood of another individual on a second. 

 The mixture was placed at once in the warm incubator and 

 examined from time to time. The amoebae were moving freely 

 amongst the blood cells, and though the red blood corpuscles 

 became adherent to the surface of the amoebae none of them were 

 ingested. It is clear, therefore, that E. coli does not readily ingest 

 red blood corpuscles under the conditions of the experiment. 



Our observations in cases of bacillary dysentery with much 

 blood in the stool, and where E. coli were present as demonstrated 

 by the subsequent occurrence of E. coli cysts alone a few days later, 

 all go to show that even in the gut where there is an abundance 

 of red blood corpuscles present the amoebae do not tend to ingest 

 them. On the contrary, all cases with amoebae showing red blood 

 corpuscles have proved on careful investigation to be cases of 

 E. histolytica infection. 



