On the influence of certain natural agents on the virulence of the tubercle-bacillus / by Arthur Ransome and Sheridan Delépine, received May 1, 1894.

  • Ransome, Arthur.
Date:
[1894]
Catalogue details

Licence: Public Domain Mark

Credit: On the influence of certain natural agents on the virulence of the tubercle-bacillus / by Arthur Ransome and Sheridan Delépine, received May 1, 1894. Source: Wellcome Collection.

Provider: This material has been provided by The University of Glasgow Library. The original may be consulted at The University of Glasgow Library.

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    We have now carried the enquiry a little further, and, amongst other objects, have endeavoured to determine how short a period of exposure to air and light would suffice to destroy the poisonous action of the microbe. We selected guinea-pigs as the most susceptible animals to test this question. In the first instance pure cultivations of the bacillus were pre- pared, and were found to be active by frequent inoculations. Small portions of this material were spread in a thin layer, upon pieces of sterilized paper. They were arranged in circles of about 2 mm. in diameter, so as to give every opportunity for the action of the elements. They were then exposed in a glass-room, with free access to air and light, i.e., close to open windows, for diminishing periods of time, viz., 14, 10, 6, 4, and 2 days respec- tively. Contemporaneous daily records were kept of temperature, maximum and minimum, and of the amount of sunshine taken through the glass roof, by means of one of Negretti and Zambra's sunshine recorders. The following table (Table II) gives the results of the meteorol- ogical observations, but as will be seen presently, only those for the first few days are of importance. No result from the other papers ; the control experiments showing that the bacilli used after this date had lost their virulence. Even the results of Experiments 97 and 98 are doubtful on that account, but Experiment 85 was made with a very virulent specimen, as was proved by the inoculation of two other guinea-pigs, with paper rn- fected with the same quantity of the same cultivation, and kept the same length of time, but not exposed to sunlight. In both these cases advanced tuberculosis was produced in 44 days. _ It may be noted that only one of these experiments can be en- tirely relied upon, and that in this case, after 4 days exposure to air and 12* hours of sunshine, there was no result from the mocu- latThese observations, though not in any way conclusive are in accord with those of Professor Koch * and they encouraged us to r^eve that even short exposures of the tubercle-bacillus, even m sputum, to air and light, might render it innocuous. _ PIn the next series of observations, it was determined to allow * Koch 'VerhandlungendesIntemationalenMedicinisclien Congresses (Berlin, * Koch, vernanu g f gome s lt haa 4th to 9th August, 1890), vol. 1, p. 35. Jlocu ^ h become known that light could lull bactena^ *e ^ST MarLll Ward's periments of Downes and Blunt, Arlomg Eou. and o has MaU ^ ^ Iperiments with the ^[fSTZ ule t - 1 u of '.Inch cultivations able to confirm.tin* ^X^kiTJt t^ of time varying from a few ' ^ S ^tX^L to diLe daylight in a roo* they were killed in from five to seven days.
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