PART II. CHARACTERS AND DIAGNOSIS 65 



(b) The Character of the Stool in Amoebic Dysentery. When 

 we come to the characters of the stool of amoebic dysentery the 

 difficulties to be encountered are much greater. When actual 

 dysentery is present the blood and mucus are much darker in 

 appearance than the blood and mucus of bacillary dysentery. The 

 blood may be black or brown, while the mucus is often transparent 

 and dark brown in colour. The blood and mucus again are more 

 often mixed up with faecal matter, and one does not have the 

 picture of the bottom of a pan covered with whitish mucus and 

 blood as in bacillary dysentery. Again, in amoebic dysentery the 

 stool may be merely a soft unformed stool, which on close examina- 

 tion is found to be impregnated with mucus intimately mixed with 

 the faecal matter. Such a stool may be termed mucoid. 



Microscopic examination of the stools of the amoebic dysenteric 

 shows nothing characteristic apart from the amoebae. Cells of many 

 kinds are present, in fact any of the cells described as occurring 

 in bacillary dysentery. But the cells are never present in such 

 numbers and one does not find that condition where the whole 

 field is covered with them. There are then no cells characteristic 

 of amoebic dysentery, but the absence of the bacillary dysentery 

 picture may lead one to assert that the case is probably not 

 bacillary. A diagnosis can only be arrived at by finding the amoebae 

 with their included red blood cells. If these are not present the 

 case may be one of some other disease, but may still be amoebic 

 dysentery, for in these cases it sometimes happens that the amoebae 

 cannot be found at the first examination. 



Another and very important point which must not be forgotten 

 in these cases is that a negative bacteriological or protozoological 

 examination does not exclude the disease. It is probably true that 

 a microscopic examination of amoebic dysenteric stools will give 

 a positive result in a few minutes more frequently than a bacterio- 

 logical examination of a bacillary dysentery stool will in as many 

 days ; but even the protozoological examination will fail sometimes. 

 To avoid such errors the stools should be examined on several 

 occasions, when the chances of error will be reduced to a minimum. 

 An instructive case in point and which has been referred to 

 above is the following. The patient, who had been invalided from 

 Mesopotamia with dysentery, was admitted to hospital in Alexandria. 

 The stool, which was a brown liquid one, did not contain evident 

 blood and mucus but microscopically there were present numerous 

 blood, pus and other cells reminding one of the picture of a bacillary 

 dysentery in the post-mucous stage with liquid stool. No amoebae 



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