DYSENTERY CAUSED BY BALANTIDIUM COLI. 151 



changes. It often has been observed that flagellates and ciliates tend 

 to group themselves together in fresh specimens. This grouping ap- 

 parently has no relation to conjugation and probably is due to mechanical 

 action alone. 



We know that the organisms multiply by division. In almost any 

 field where they are numerous, either in stained sections from colonic 

 ulcers or in stained fseces, partial or complete division of the nucleus 

 may be seen. Balantidia with central constriction may be found in fresh 

 specimens as may also many very small, elongated young forms which 

 seem to be the result of this division. As yet we have had no success 

 as to cultivation. I have observed balantidia alive forty-eight hours after 

 inoculation on Musgrave and Clegg's amoeba medium, and Walker in this 

 laboratory has noted life for one week on the same medium, biit the balan- 

 tidia apparently had not reprodiiced and those which remained alive were 

 left from the original individuals which had been inoculated. 



In view of the fact that Brooks has reported an epidemic of dysentery 

 due to Balantidium coli among the apes of the New York Zoological 

 Park * and jSToc F.^ a natural infection in a monkey {Macacus cyno- 

 molgus Geoff.) we would expect to be able to produce the disease experi- 

 mentally in monkeys. 



I have attempted to infect monkeys, but have been unsuccessful. Fresh 

 fasces from a case of severe infection were many times injected into the 

 rectum and the monkey suspended by his lower extremities in order that 

 none of the material could be evacuated. Frequent examinations showed 

 no balantidia present. 



A colotomy was also performed on another monkey and 20 cubic 

 centimeters of infected faeces were injected into the colon on two occasions. 

 The organism never appeared in the faeces. 



Some tissue from an ulcer removed at the autopsy reported in this 

 paper was inserted beneath the mucosa of the colon of a monkey and well 

 sutured in. This operation was done in the hope that in the tissue of 

 the ulcer, resting or encysted forms might occur which would be more 

 resistent to manipulation and conditions incidental to the changing of 

 the host, and which might develop and infect the animal. No balantidia 

 were ever found in the faeces, nor were any symptoms of dysentery noted. 



I have never seen anything which could possibly be construed as an 

 encysted Balantidium coli in fresh faeces, although many round, vacuo- 

 lated, nonmotile organisms were found in old specimens. In a short time 

 these organisms became flattened and irregular, and extruded granular 

 degenerative material from the periostome. 



*Z^. Y. Aniv. Bull. Med. Sci. (1902), January. 

 ' Compt. rend. 8oc. liol. (1908), 64. 



