23 



Table B — Continued. 



> HCl 1-5,000. 2 HCl 1-2,500. 



In examining the foregoing table the following results will be 

 noted : 



Boric-acid solution as strong as 1-25 had practically no effect 

 on the amoeba or the cholera spirillum after an exposure of two 

 hours. 



Tannic acid 1-100 after thirty minutes had a moderate effect on 

 the viability of the amoeba apparently by destroying almost all of 

 tlie cholera spirilla in the culture. 



Succinic peroxide acid exercised a marked deterrent effect on the 

 growth of the amoeba by destroying most of the spirilla, as was 

 demonstrated by the fact that the transfers to cholera plates always 

 contained a much larger proportion of amoebse than did tlie syn- 

 chronus transfers to sterile agar plates. For benzoyl-acetyl peroxide 

 see preceding table. 



Nitrate of silver showed a marked destructive effect l)oth on 

 amoebje and on bacteria, 1-2,000 applied for fifteen minutes 

 destroying the bacteria and leaving a very slight growth of am(vl)a3 

 on both sterile and cholera plates; 1-500 destroyed both aiiKebre 

 and spirilla in thirty minutes. 



Among the colloidal silver salts tested, argyrol as weak as 1-500 

 ni)plied fifteen minutes exercised an effect similar to that of suc- 

 cinic peroxide acid and protargol; 1-500 applied for one hour left 

 almost no surviving spirilla and very few ama'b.v. 



