Apr. 15, 1915 Disinfection of Hides 73 



The loop used was 3 cm. in diameter of 23-gauge platinum wire. The 

 preparations so made were dried in the incubator 23 hours and then kept 

 at room temperature until used. 



In view of statements made by Otsuki (8) that spores of anthrax are 

 injured by drying at 37.5° C, and that the best method of preparation is 

 by drying them at 10° C, another lot of test preparations of hide was 

 made as follows: Pieces of hide were cut to weigh about 2j^ gm. On 

 each piece a good-sized drop of blood from a rabbit's ear was allowed to 

 fall and into this was mixed a loopful of a suspension of anthrax spores. 

 This suspension was prepared by rubbing up in sterile water enough of 

 the surface growth from a 15-day agar culture to give a suspension ap- 

 proximately equal in density to a 24-hour bouillon culture of Bacillus 

 typhosus. These pieces of hide were placed in Petri dishes with raised 

 covers and were dried for three days in a desiccator over sulphuric acid 

 at a temperature of 10° C. and in a vacuum equal to about 6 cm. of 

 mercury. 



Guinea pigs were inoculated with clots from pieces of hide dried by 

 each method. In neither case were the spores found to possess suffi- 

 cient vitality to infect the animals, and it seemed evident that the methods 

 of preparation had in some way attenuated the virulence of the spores. 

 In view of the statement made by Roos (11) that rabbit blood is bac- 

 tericidal for anthrax bacilli, while guinea pig blood is not, it seemed that 

 the lack of virulence might be due to the use of rabbit blood. Therefore 

 new pieces of hide were prepared, using blood from a guinea pig instead 

 of rabbit blood as before. The pieces of hide were dried for 24 hours 

 at 37.5° C. and then kept several days at room temperature in a dark 

 closet. The lower drying temperature was used in later experiments. 

 The spores in these test preparations were found to be virulent for 

 guinea pigs, although less virulent than the original A. M. S. culture 

 when tested shortly after it was received. 



The virulence of the cultures was therefore raised by successive inocu- 

 lations until a culture was obtained which killed a guinea pig in about 

 36 hours after subcutaneous inoculation. This culture was then em- 

 ployed in preparing test pieces of hide by the method above described, 

 guinea-pig blood being used and the pieces being dried at 37.5° C. The 

 pieces of hide so prepared were subjected to the following tests : 



Each piece of hide was exposed to 25 c. c. of disinfectant for 24 hours 

 and then soaked in 25 c. c. of saturated salt solution for 24 hours. At 

 the end of that time the clots were scraped off and inoculated into guinea 

 pigs. The results are given in Table VI. 



