27 



In accordance with the above suggestions suspensions of anuebte 

 and cholera spirilla of varying degrees of concentration were poured 

 into clean copper crucibles, covered, and allowed to stand at room 

 temperature in ^Manila for five days. At the termination of nine- 

 teen hours and ©f five days, transplants were made in the usiuil 

 manner with the following results: 



Suspension A (4 cuhic centimeters to one slant agar culture) 

 developed a good growth of amci^bffi and spirilla from transplants 

 made after standing nineteen hours in the copper crucihle, and a 

 fair growth on cholera plates after five days, though none on sterile 

 agar plates. 



Suspension B (8 cubic centimeters to one slant agar culture) 

 'developed a slight growth of both amoebae and spirilla on sterile 

 agar plates from transplants made after standing five days, and 

 a rich growth on cholera plates. 



Suspension C (12 cuhic centimeters to one slant agar culture) 

 gave results identical Avitli those of suspension A. 



It would appear from the preceding results that it would be 

 disastrous to rely on the action of copper containers to purify water 

 infected with amcebas or cholera spirilla and that Moore's claim 

 quoted above can not be substantiated, at least as far as it relates to 

 the organisms used in my experiments. 



As previously stated in this report, amceba No. 11524 was chosen 

 as a standard because of its proven j^athogenicity and its sturdy 

 resistance to unfavorable conditions. It was taken for granted that 

 any chemical substance which would destroy amoeba 11524 would 

 destroy most of the others, and the few experiments I had time 

 to carry out in that connection justified the assumption. 



The amoebfe employed in these control experiments were 

 Xo. 39888, a small intestinal amoeba isolated by Dr. Musgrave 

 from a case of intestinal ama^biasis and cultivated in symbiosis 

 witli the cholera spirillum, and amoeba tap "A," isolated by 

 myself from the jManila water supply, drawing the water from the 

 laboratory tap. The latter amoeba was cultivated in pure strain 

 from a single individual, in symbiosis with two or three varieties 

 of water bacteria among which a yellow pigment-forming bacilhis 

 predominated almost to the complete exclusion of the others. 



These two amoebae were tested with sulphate of quinine 1-1,000 

 (HCl 1-5,000), thymol 1-5,000, acid succinic peroxide 1-1,000 



