Action of Certain Antiseptics. 



125 



182 (1360) 



Studies on the action of certain antiseptics, toxic salts, and alka- 

 loids against the bacteria and protozoa of the intestine of the 



rabbit 



By A. K. Balls and Jose D. Moral. 



[From the Department of Bacteriology, Columbia University.} 



The authors believe from theoretical considerations that there 

 is a difference in the susceptibility of bacteria and protozoa to the 

 action of antiseptics. This difference is found to exist between 

 the intestinal bacteria and the intestinal protozoa (Giardia cuni- 

 culi) of the rabbit, when treated with certain dilutions of chlor- 

 amine T, brilliant green, "Halazone" and copper sulphate. 



In these cases the protozoa are more resistant than the bac- 

 teria. Therefore bacterial-free material containing live protozoa 

 is easily obtained. 



This behavior does not hold for free living protozoa which are 

 more sensitive to the action of these same antiseptics than the 

 bacteria which accompany them in nature. Free living protozoa 

 are also less resistant when compared with parasitic protozoa. 



Increase in temperature greatly increases the effect of the 

 antiseptics, especially against the protozoa. 



The authors conclude: 



(1) In the intestinal content of the rabbit, it is possible to show 

 that resistance of Giardia cuniculi against the action of certain 

 antiseptic substances is markedly greater than the resistance of the 

 intestinal bacteria. It is possible by making use of this difference 

 in resistance to obtain Giardia free from all living bacteria, but 

 attempts to subsequently grow them in pure culture have not 

 succeeded. (2) The Giardia are more resistant to the action of 

 these toxic substances than are the free living protozoa studied. 

 (3) A technical method has been developed which we believe will 

 be useful in demonstrating the applicability of intestinal anti- 

 septics against both the protozoa and the bacteria of the intestine. 



