ENTAMOEBA COLI 73 



organisms which he found were, for the most part, Entmuoeha colt — the 

 same as the amoebae observed by Cunningham : and they were not 

 Losch's " Amoeba coH," which was Entamoeba histolytica. This wrong 

 identification has been responsible for much of the confusion which 

 arose later. Grassi, moreover, not only saw E. coli in the amoeboid 

 stage : he also saw its cysts. But he mistook these for coccidia,* and 

 described them as such (Grassi, 1879). His figures (1879, figs. 10 and 

 II) are conclusive in this respect. Later, he himself confessed that his 

 "coccidia'" were "resting amoebae," or cysts (Grassi, 1882, 1883, 1888). 

 Grassi's second account (1882, 1883) of his "Amoeba coli" is brief, and is 

 accompanied by an unrecognizable figure of the organism. He says it 

 occurs in healthy people, as well as in those suffering from diarrhoea or 

 other intestinal ailments : but as it lives in the more fluid part of the 

 contents of the colon, it is most abundant in the stools when these are 

 soft or diarrhoeic. With Cunningham he regarded the organism as non- 

 pathogenic. It was stated to measure 8-22 /jl in diameter, its nucleus 

 being 2.2 — 5.5 /i and round in shape, "with 2 (? always) nucleoli." The 

 ectoplasm was said to be very thin, the endoplasm granular and con- 

 taining numerous vacuoles filled with food of all sorts — starch grains, 

 bacteria, etc. 



In a later paper Grassi (1888) gives some further details concerning 

 his " Amoeba coli." He says the organism encysts in the same way as 

 Endamoeba blattaeA The cysts are smaller than the amoebae ; they 

 contain " more or less numerous (3, 6, 9) luiclei," and are diagnostic of 

 the species. He adds the important statement that he and Calandruccio 

 — with whose collaboration the above observations were made — have 

 shown " by repeated experiments " that human beings, when they 

 swallow the cysts, acquire infection with the amoebae, which multiply 

 by fission in their new host. Calandruccio (1890) has confirmed these 

 statements. Grassi (i888rt) reaffirms his belief that the amoebae are 

 harmless to man — "they are simple commensals, altogether innocuous." 

 He says he has found them present in enormous numbers in the stools 

 not only of persons suffering from dysentery, but also of those with 

 many other disorders — typhoid, cholera, pellagra, simple diarrhoea ab 

 ingestis, etc. — and in the stools of perfectly healthy people, who often 

 continue for months to pass the cysts in large numbers. The infection 

 experiments noted above were not followed by dysentery or other intes- 

 tinal derangement. 



From the foregoing it is abundantly clear that Grassi studied chiefly 

 the amoeba here described as Entamoeba coli, though he did not count 

 the nuclei in the cysts correctly — the numbers he givesj being very 

 unusual, and the typical number (8) in the mature cyst not being 

 mentioned. It should be noted that Grassi mentions (1883, i888fl) that 

 his "Amoeba coli" will ingest red blood corpuscles, when these are 

 present in the intestinal contents. It thus seems probable that he also 

 saw E. histolytica, but did not distinguish it from the commoner form. 



* For further details concerning Grassi's "coccidia" see my paper on the coccidia 



of n-an (Dobell, 1919). 



t Grassi (1888) incorrectly called this organism "Amoeici blattarum." 



% Calandruccio's (1890) statements concerning the number of nuclei in the cysts 



of E. coli are identical with Grassi's. 



