82 Journal of Agricultural Research voi. iv, no. i 



HYDROCHLORIC ACID AND SODIUM CHLORID 



In view of the apparent inefficiency of the Seymour-Jones method 

 and the favorable results reported by various workers using the Schat- 

 tenfroh method, experiments were now undertaken to determine the 

 germicidal power of hydrochloric acid and sodium chlorid against 

 anthrax spores, both as "naked" spores and as contained on and in 

 infected pieces of hide. The Schattenfroh method (12) as described by 

 Prof. Schattenfroh consists of immersion of hides in solutions of hydro- 

 chloric acid and common salt, the proportions recommended varying 

 according to temperature. The proportions recommended for use at 

 room temperature are 2 per cent of hydrochloric acid plus 10 per cent of 

 sodium chlorid, with the time of exposure 48 hours. At higher temper- 

 atures less of the acid is needed and the time of exposure is shortened, 

 but inasmuch as special apparatus would be needed to maintain these 

 higher temperatures it seemed that disinfection at these higher tempera- 

 tures could be disregarded as being of little practical significance. 



The experiments here described were therefore carried on at room 

 temperature. In all cases dilutions were calculated upon the percentage 

 of absolute hydrochloric acid, not upon the percentage of "concentrated 

 hydrochloric acid." In accordance with Schattenfroh's recommenda- 

 tions, a sodium-carbonate solution was used after exposure to the disin- 

 fectant, in order to neutralize the hydrochloric acid. 



I. EXPERIMENTS BY THE ROD METHOD, USING SPORES OF BACILLUS ANTHRACIS 



A series of experiments was first made by the rod method, using various 

 proportions of hydrochloric acid and sodium chlorid. The time of exposure 

 in each case was 24 hours, and rods were washed with a 2 per cent solution 

 of sodium carbonate to neutralize the hydrochloric acid. Experiment 

 23 (Table X) was made without the addition of organic matter; experi- 

 ment 24 (Table X) was made with the addition of i c. c. of defibrinated 

 blood to 9 c. c. of disinfectant in each tube. The results are given in 

 Table X, together with the results of an experiment upon mercuric 

 chlorid, alone and with acetic acid and formic acid, which was made at 

 the same time, and with rods infected by the same spore suspension. This 

 suspension was rather heavier than usual. In experiment 24 the hydro- 

 chloric-acid rods were washed in a 20 c. c. sodium-carbonate solution for 

 one minute, and the mercuric chlorid rods in a 20 c. c. saturated hydrogen 

 sulphid for one minute. 



