A bacteriological study of methods for the disinfection of hides infected with anthrax spores / by F.W. Tilley.

  • Tilley, Frank W.
Date:
1915
Catalogue details

Licence: In copyright

Credit: A bacteriological study of methods for the disinfection of hides infected with anthrax spores / by F.W. Tilley. Source: Wellcome Collection.

    29/36 (page 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, 2% 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 Sev£lk (14) and