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.

    28/36 (page 88)
    As a part of experiment 32, plates were made from the material scraped off the pieces of hide. In every instance the plates made from material treated by 2 per cent of hydrochloric acid and 10 per cent of sodium chlorid were sterile. On the other hand, growth was observed on all the plates from material exposed to mercuric chlorid and formic acid. In this experiment, as in several of the last few experiments described in the previous discussion of the Seymour-Jones method, it will be noted that material from pieces of hide exposed to mercuric chlorid and formic acid and treated shortly after completion of the disinfection with sodium sulphid failed to kill guinea pigs into which it was inoculated. On the other hand, material from pieces of hide allowed to stand for several days before using sodium sulphid caused guinea pigs to die from anthrax. It was noted that the depilatory action of the sodium sulphid was far more complete in the case of the pieces of hide which had been kept for several days after disinfection before treatment with the sulphid. The results of plating, as before mentioned, showed that disinfection was not complete; therefore it seems probable that the more extensive depilatory action of the sodium sulphid upon pieces which had stood for some time brought up from the depths of the hair follicles spores which had been practically untouched by the disinfectant. It also seems possible that there had been some development and multiplication of these uninjured organisms during the period of waiting. It should be noted that in the preparation of the pieces of hide used in all the above-mentioned experiments particular care was taken to secure penetration of the spores into the pieces of hide. In order to accomplish this, the pieces of hide after being infected by spore suspensions were placed in closed Petri dishes and kept in the ice box for four or five hours before the drying process was begun. As will be seen by reference to Table XIII, the Schattenfroh method was entirely successful in every instance, and the results of plating showed that actual sterilization was accomplished. Experiment 33 (Table XIV) was exactly similar to the preceding ex¬ periment except that the pieces of hide used were infected by spores derived from a different culture. The method of preparation was the same as that described under experiment 31. In this experiment, as in the preceding one, the efficiency of the disin¬ fectants was tested by plating out material from the pieces of hide. The results obtained varied from the results of experiment 32 in that a few colonies were found on two plates from material treated with hydro¬ chloric acid and salt, while all other plates from similar material were sterile. One plate from material neutralized by 0.5 per cent of potas¬ sium hydrate showed two colonies, while the other, from material neu¬ tralized by sodium carbonate, showed one colony. In none of the three was Bacillus anthracis the organism present. Therefore, although hydro-