94 AMOEBAE LIVING IN MAN 



thesis that "the specific cause of pyorrhea dentalis and alveolaris is 

 endamebas." All these workers went a step further and claimed that 

 emetine has a specific therapeutic action in " oral entamoebiasis " — 

 comparable with its action on E. histolytica in amoebic dysentery. These 

 statements have been the subject of much controversy, and have been 

 productive of a considerable amount of literature on the medical side. 

 As they have now been to a great extent disproved, and as the controversy 

 has little zoological interest, it will be unnecessary to consider it here in 

 detail. The special points arising from it — in so far as they are concerned 

 with the amoebae themselves — will be considered later. 



On account of the supposed " specific relation " of the organism 

 to disease, and the " specific action " of emetine upon it, some workers 

 have even been led into discussing whether £. gijigivalis is not really 

 identical with E. histolytica. Smith and Barrett (191 5), for instance, 

 suggested this possibility ; but later (1915^1) they abandoned the hypothesis, 

 and concluded that the two organisms are specifically distinct.* Although 

 the characters which distinguish E. gingivaiis from the intestinal amoebae 

 of man appear at first sight somewhat indefinite, there can be no doubt 

 now, I think, that it is an entirely independent species. Its resemblance 

 to E. coll, noted by Prowazek (1904), or to E. histolytica, as stated by 

 Smith and Barrett (1915), is not, I think, very striking to anybody 

 familiar with all these species. 



It may be added that the organism called "Amoeba pultnonalis" by 

 Artault (1898) may possibly have been E. gingivalis : but I consider that 

 the bodies which he saw were probably not amoebae but cells. Brumpt 

 (1910, 1913), however, says he has also seen the organism, and gives 

 some diagrams of it. He calls it Entamoeba pnlmonalis (Brumpt, 1913), 

 and says it may be identical with E. gingivalis. It seems to me not 

 improbable that Brumpt's " E. pnlmonalis " really was £. gingivalis, and 

 was wrongly referred to Artault's species. Consequently, I have taken 

 this view in enumerating the synonyms of E. gingivalis at the head of 

 this section. It also seems not unlikely that the "ameba" found by 

 Lynch (1915 a) in the lower jaw of an American negress suffering from 

 " suppurative and hyperplastic osteoperiostitis," was really E. gingivalis. 

 The author considers that it belonged to a new species, but as he has 

 not studied or described the organisms properly — having accidentally 

 destroyed his preparations — it is unnecessary to discuss this possibility. 

 Since Kartulis and Flexner described " amoebae " from maxillary 

 abscesses, many similar cases have been recorded, and at present there 

 seems to be no sufficient reason to suppose that the organisms observed 

 were not £. gingivalis in every case. Most of the descriptions are too 

 meagre, however, to prove this conclusively : and 1 have little doubt 

 that some at least of the " amoebae " found in suppurative conditions in 

 and about the mouth have been endothelial or other cells, and not 

 amoebae of any sort. 



Craig (1916) records it as his opinion that " in all probability, further 



• These authors (191 5 a) attempted to infect kittens with E. gin^valishy feeding 

 them on pyorrhoeal pus rich in amoebae, and by injecting the amoebae into the recluni, 

 or into the colon after laparotomy. They also injected amoebae per rectum into two 

 puppies. All the experiments had negative results. They concluded that E. gingivalis 

 IS specifically distinct from E. histolytica, and that " intestinal infestment " is " probably 

 impossible." 



