Apr. IS, 191S Disinfection of Hides 89 



chloric acid and salt did not accomplish actual sterilization in every 

 instance, it did destroy anthrax spores in every instance. 



Several pieces of hide about 50 gm. weight each were exposed to 2 per 

 cent of hydrochloric acid plus 10 per cent of sodium chlorid for 48 hours 

 and thoroughly washed with 3 per cent sodium-carbonate solution. 

 They were then examined and tanned in the Leather and Paper Labora- 

 tory of the Bureau of Chemistry, along with pieces of hide which had 

 been treated by other disinfectants. This work was in charge of Mr. F. P. 

 Veitch, and the result is shown in his memorandum on page 91. 



OTHER DISINFECTANTS 



Bacteriological tests were made with formalin and phenol, and pieces 

 of hide treated by these disinfectants were examined and tanned in the 

 Leather and Paper Laboratory of the Bureau of Chemistry. Without 

 going into details it may be stated that, so far as could be determined 

 by the limited number of tests, 2K per cent of formalin is efficient bac- 

 teriologically both against anthrax spores and against other organisms, 

 while 5 per cent of phenol is fairly efficient against non-spore-bearing 

 organisms, but is practically useless against anthrax spores. It should 

 be noted also that pieces of hide disinfected by formalin in 2^ per cent 

 solution were so seriously affected by the disinfectant that it was almost 

 impossible to tan them, while pieces treated with carbolic acid were 

 uninjured. 



A few tests were made of the germicidal efficiency of mercuric-chlorid 

 solutions saturated with sodium chlorid. It was found that this combi- 

 nation is, if anything, not as efficient as mercuric chlorid alone. This is 

 presumably due to interference of the salt with the ionization of the 

 mercuric chlorid, as the work of Kronig and Paul (6) quite clearly 

 indicates. 



During the course of the investigations herein recorded, the writer 

 noted considerable variations in the vitality and virulence of anthrax 

 spores from different sources. It was also noted that the processes 

 employed in infecting and drying test preparations exercised a variable 

 influence upon the vitality of the spores. In view of these variations, 

 it was found to be necessary to repeat the tests many times, and in 

 order to test the various methods as thoroughly as possible, every effort 

 was made to maintain at the highest possible point the vitality and 

 virulence of the spores used in test preparations and to make sure of 

 the presence of a considerable number of such spores upon each test 

 preparation. 



It seems likely that anthrax spores occurring upon naturally infected 

 hides might in many cases be present in much smaller numbers and 

 possess far less vitality and virulence than those used in the experi- 

 ments. However, in view of the results obtained by SevCik (14) and 



