Report to the Local Government Board / by R. Angus Smith.

  • Smith, Robert Angus, 1817-1884.
Date:
1882
Catalogue details

Licence: Public Domain Mark

Credit: Report to the Local Government Board / by R. Angus Smith. Source: Wellcome Collection.

    14/136 (page 8)
    ready to putrefy ought to be avoided, as we cannot tell when the moment of danger begins, whilst the quality at best is never known to us exactly, To ascertain the nature of the organic matter the water is allowed to stand for a day or two, in which case it may be found that organised bodies show themselves. Sometimes plants seem completely to fill the vessel, having come out of a moderately clear solution. When standing in this case, the water must be prevented from evaporating, and it must be in glass, so as to be exposed to light; a temperature suiting vege- tation is also to be given. Animalcules may appear in great numbers. They are an indication of nitrogenous matter, and one proof of the presence of substances capable of putrefaction. It may be that some form of putrefaction will be the only result; but whether this occurs alone, or along with organised forms, an excess of organic matter is proved. Water that will not bear the test of standing will in most cases be rejected at once. If no other can be obtained, it ought to be used before the putrefactive process has begun; but this is very dangerous. The next best method is to wait till after putrefaction has terminated, and the products are separated as much as possible. This is popularly known to be the case when the water has for some time become clear and colourless and fi'ee Irom smell and. taste. Water with green organic matter in suspension or semi- solution is generally full of germs of living things and nauseous to the taste. The oxidation of nitrogen has been a favourite subject of late, but I should not think of attending to it for that reason. However, it may be known to a few chemists that I made nitric acid or nitrates from organic matter in water at a very early stage, as seen in the vol. of the Trans, of the British Association in 1848. I cannot, therefore, be said to be late in the field. Regarding the deoxidation I may quote from my paper of 1867, speaking of nitrates : the oxygen seems to be removed as the oxygen of the air is, leaving the nitrogen to pass off as gas. Mem. Lit. and Phil. Soc. of Manchester, vol. 4, ser. 3rd, 1867-8. When doing the first experiments, spoken of in 1848, I used generally, if not always, yeast for the organic matter, and I did not give to the organised bodies the credit of producing the action. The interesting experimentp, however, of M. Schloesing and of Mr. llobert Waringtun cause eveiy one to reconsider the subject. I suppose M. Pasteur gave the first idea of the action of organisms in nitration, but, so far as I remember, did not prove it. The idea that all nitrates are the pi'oducts of oxida- tion of animal matter in contradistinction to vegetable is another point which compels us to think over the subject. I have always objected to the opinion that tliey were the products special of animal life, knowing that my own experiments were made with vegetable substances. It has, on the other hand, been said (long ago in conversation with me,—I do not remember