8 



The Philippine Journal of Science 

 Table I. — The balantidicidal action of various chemicals. 



UlS 



Substance tested. 



Balantidicidal action. 



Dilution. 



Atoxyl 



Sodium arsenate -. 



Antimonyl potassium 

 tartrate. - 



Trypan red.._ 



Methylene blue (medici- 

 nal) - --- 



Fluid extract of ipecac. 



Emetine hydrochloride.. 



Quinine hydrochlorate . . 



Copper sulphate . 



Mercuric chloride 

 Mercuric iodide . . 



Silver nitrate 



I (5-10 

 Imin.) 



+ 

 (10-15 

 min.) 





 



+ 



(60 



min.) 



-I- 



(60 



min.) 



+ 



(80 



min.) 



+ 



+ 



+ 



+ 



(in- 

 stantly) 



l« 



+ 



min.) 

 f + 



(in- 



Istantly) 



+ 



(2-15 



min.) 



This series of tests presents some interesting and unexpecte(i 

 results. 



In the first place, it is noteworthy that the compouncJs of 

 arsenic and antimony and the aniline dyes, which have been 

 so extensively employed with more or less success in the treat- 

 ment of other protozoan diseases, especially the trypanosomia- 

 ses, have proved to possess little or no balantidicidal action. 

 Atoxyl, sodium arsenate, antimonyl potassium tartrate, and 

 trypan red are absolutely inert in the low dilution of 1 part 

 in 100 after acting for one hour on Balantidium coli.^ Med- 

 icinal methylene blue is scarcely more active, a part only of 

 the balantidia being killed after exposure for one hour to a 

 dilution of 1 part in 100 of this dye. 



' However, the fact should not be overlooked that some of these substances 

 may be more balantidicidal in vivo than in vitro. Such has been found to 

 be the case with certain arsenic compounds in the treatment of trypanoso- 

 miasis. 



