132 THE AMOEBAE LIVING IN MAN 



Mathis (1913 a) has shown that the Tonkin monkeys (Macacus rhesus 

 and M. tcheliensis) are commonly infected with two species of Entamoeba 

 which appear to be indistinguishable from £. coli and E. histolytica. 

 The one, with 8-nucleate cysts, he named Loschia legeri ; the other, with 

 4-nucIeate cysts containing chromatoid bodies, L. duboscqi. Mathis 

 thus regarded these species as distinct from the closely similar forms in 

 man, and Mathis and Mercier (1917 c) have since attempted to show that 

 morphological differences exist between E. coli and E. legeri. They fail 

 to prove their case, however, and advance no character of the latter which 

 may not also be discoverable in the former. 



Prowazek (1912 a) had previously found an Entamoeba in an orang- 

 utan (Simla satyriis), and named it E. pitheci. This " species " appears to 

 be a mixture of Mathis's two species. Later, Behrend (1914) found 

 amoebic cysts in M. rhesus — said to resemble those of E. coli, but 

 measuring 8-25 fi in diameter, and apparently also belonging to both 

 the species of Mathis. 



Swellengrebel (1914) has also described an Entamoeba, which he 

 named E. chattoni, from M. rhesus. It appears to resemble a strain of 

 E. histolytica which forms small cysts — the diameter of the cysts of 

 E. c/ja/<OHi being given as 8-9 /i. It is said further, however, that no cysts 

 with more than two nuclei were ever found. Swellengrebel identifies his 

 amoeba with that of Chatton (1912 a), but not with those of other authors. 

 Macfie (19 1 5) has recorded an amoeba from a monkey (Cercopithecus 

 petaurista) on the Gold Coast. It was believed to have caused a fatal 

 dysentery to its host, though the evidence appears inconclusive. It is 

 said to measure 12-30 /* in diameter (stained), and to contain both bacteria 

 and red blood corpuscles. No cytological characters of any systematic 

 value are recorded. The organism is said to form cysts, with a diameter 

 of 12 /i to 33 /i : but the figures of them show unmistakable specimens of 

 Blastocystis. The amoeba was named Entamoeba cercopitheci. 



Finally, Eichhorn and Gallagher (1916) in America record an out- 

 break of spontaneous amoebic dysentery among captive spider monkeys 

 (Ateles ater). Eight showed typical amoebic ulceration of the intestine, 

 and two developed amoebic liver abscesses. The amoebae are quite 

 unrecognizable from the figures. The authors state that " no special 

 attempt was made to determine the species of the amebas concerned " ; 

 and they also state that attempts to infect cats by feeding them on 

 dysenteric stools containing the amoebae were unsuccessful. They 

 conclude that " these negative transmission experiments suggest that the 

 parasite found is of a different species from that in man." It is obvious, 

 however, that such an experiment is meaningless, and would have been 

 equally negative if they had made it with active forms of £. histolytica. 



From the foregoing * it seems fairly clear that several different species 

 of monkey are infected with at least two different Entamoebae, which are 

 not yet distinguishable with certainty from E. coli and E. histolytica. 

 Monkeys appear, moreover, to be subject to amoebic dysentery and 



* I have not included some observations recorded by Greig and Wells (191 1), who 

 state that they were able to cultivate amoebae from the faeces of 53 monkeys {Macacus 

 sp. ?) ; because in their tables I can find no evidence that they found parasitic amoebae in 

 any of their animals. Craig's (1912 a) statement that these authors found amoebae 

 indistinguishable from those of man in all the 53 monkeys they examined therefore 

 appears to me to be incorrect. 



