Some experiments with disinfectants 13 



conditions were adhered to. It was conducted in all respects according 

 to the recommendations of the New Hampshire Board, 2| pints of 

 formaline and 8J ounces potassium permanganate being employed. The 

 temperature of the air was 51-5° R, and the relative humidity was 83 %. 



The organisms used in this experiment were : — 



1. actively sporing B. anthracis. 



2. 24 hours' culture on agar of Staphylococcus pyogenes aureus. 



3. B. typhosus. 



4. B. coli communis. 



Technique. — The technique employed was similar to that of the 

 previous experiments, that is, the exposure of glass slips coated with 

 dried emulsions of the various organisms. Control experiments were 

 made at the same time with similar slips kept in a sterile Petri dish in 

 the laboratory. 



The other slips were distributed in the house, as in experiment i, 

 viz. : — 



1. on floor, behind main door. 



2. upon the shelf, 7 feet from the floor, near the vessel. 



3. upon mantelshelf, above fireplace. 



4. upon ledge, above window. 



5. on floor of one of the smaller rooms, in a corner remote from the 



door. 

 They were exposed to the action of the disinfectant for 3 hours. 

 The exposed slips, and the control slips, were then placed direct into 

 bouillon tubes, and incubated at 37° C. Within 24 hours growth was 

 present in all the control tubes. At the end of 7 days, the following 

 results were observed in the tubes containing the exposed slips : — 



In the first set (floor of main room) growths were observed in the 

 Anthrax, Staphylococcus, and B. typhosus tubes, while the B. coli tube 

 remained sterile. 



In the 2nd set (shelf near to vessel) growth was observed in the 

 Anthrax tube, while the other tubes were sterile. 



In the 3rd set (mantelshelf above fireplace) growths were observed in 

 the Anthrax and B. typhosus tubes, while the Staphylococcus and B. 

 coli tubes remained negative. 



(249) 



