Some experiments on the disinfection of rooms by gaseous formaldehyde.
- Date:
- [between 1890 and 1899]
Licence: Public Domain Mark
Credit: Some experiments on the disinfection of rooms by gaseous formaldehyde. 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.
5/16 page 5
![5- On these brackets are placed the tubes, dishes, &c., containing the tests, or small vertical wooden boards, to which the test objects may be fixed in various ways. Test Objects.—! have found it convenient to reduce the number of micro-organisms used for the purpose of testing aerial disinfectants to a few which are capable of being dried for many days without^ sensibly losing their power of growth, either in artificial media or in livmg tissues. Some of these are sporing organisms, and have a high degree of resistance. Others are, so far as we know, non-sporing, and are readily killed. The tubercle bacillus in sputum is used to test at the same time the action of the disinfectant on the bacillus, and its penetrating power with regard to morbid discharges fresh or dry. I usually exclude from this list of test cultures those of the typhoid bacillus and of the vibrio of cholera, which do not stand drying well, and are readily killed by most disinfecting agents having any claim to efficiency. I think also that the bacillus of diphtheria is not a very suitable organism, either for cultivation or inoculation experiments. For these reasons the following microbes seem to me most convenient for testing gaseous disinfectants :— (1) Bacillus coli communis in young or old cultures, thick emulsions of the culture on agar being used to impregnate sterilised threads, fabrics, or porous paper. (2) Bacillus pyocyaneus in young or old cultures, thick emulsions of the culture on agar being used as in No, i. (3) Staphylococcus pyogenes aureus in young or old cultures, thick emulsions of the culture on agar being used as in No. i. (4) Bacillus subtilis, sporing, in young or old cultures, thick emul- sions of the culture on agar being used as in No. i. (5) Bacillus anthracis, sporing, in young or old cultures, thick emulsions of the culture on agar being used as in No. i. (6) Bacillus tuberculosis in sputum, fresh or dry, in capsules or spread on paper. (7) Horse manure, with highly-resistant sporing bacilli, in young or old cultures, thick emulsions of the culture on agar being used as in No. i. I think a disinfectant capable of killing the six first organisms exposed to it in various states and under various conditions is, for practical ]^>ur- poses, a reliable disinfectant. If, in addition, it is capable of/destroying the spores usually found in horse manure, and which often can resist for half an hour or more the action of saturated steam at 100° C., the disinfectant may be considered as exceedingly powerful. The papers, fabrics, and threads infected with the test cultures were exposed either damp or dry to the action of the gas in the followinf ways :— ° (a) In small glass capsules, loosely covered or uncovered.](https://iiif.wellcomecollection.org/image/b21454280_0007.jp2/full/800%2C/0/default.jpg)
