340 



The Philippine Journal of Science 



1913 



Table II. — Showing the number of times Balantidium coli was found 

 in the stool examinations of parasitized monkeys. 



Monkey 

 No- 



Days 

 under 

 observa- 

 tion. 



Total 

 number of 

 stool ex- 

 aminations. 



Positive. 



1 



Nega- 

 tive. 



Remarks. 



lo 



152 



44 



2 



42 





11 



38 



3 



1 



2 





26 



114 



68 



12 



46 





27 



44 



16 



3 



13 





28 



88 



55 



1 



54 





29 



58 



54 



17 



37 





30 



73 



39 



3 



36 





31 



42 



16 



4 



12 





32 



54 



22 







22 



Balantidia found at 

 necropsy. 



35 



13 



5 



1 



4 





36 



50 



33 



2 



31 





38 



50 



35 



7 



28 





39 



50 



31 



13 



18 





40 



38 



26 



3 



23 





42 



38 



28 



1 



27 



Balantidia found on 

 day after feeding. 



43 



35 



23 



5 



18 





The small number of stool examinations made of some of the 

 monkeys was due to my absence from Manila. With but few 

 exceptions, the stools were formed and contained only encysted 

 balantidia ; when the stools were soft or diarrhoeal, the balantidia 

 were sometimes found in large numbers in the motile stage. 

 In most of the positive examinations the balantidia were few in 

 number, often only one or several to a cover slip. It would 

 appear from these results that monkeys parasitized with balan- 

 tidia from either the pig or man show a condition, with reference 

 to the appearance of the parasites in the stools, more closely 

 resembling man than the pig; that is, the balantidia appear 

 rarely and in small numbers in the formed stools of the para- 

 sitized animal. In consequence of this the incubation period 

 of the parasite, that is, the time elapsing between feeding or 

 injecting the infectious material and the appearance of the balan- 

 tidia in the stools of the parasitized animal, is of little sig- 

 nificance. 



These experiments, therefore, prove that monkeys are readily 

 parasitized with either Balantidium coli hominis or Balantidium 

 coli suis. Furthermore, they make it evident that the apparent 

 failure of every previous investigator, with one exception 

 (Brumpt, 1909), to parasitize animals — at least monkeys — 

 probably has been due to the inf requence, and often total failure, 



