Dr. R. Angus Smith on the Development of Living Germs in Water.
Dr. R. Angus Smith contributed a note on the development of fixing germs in water to a recent meeting of the Manchester Literary and Philosophical Society.
Dr, Smith mentions previous attempts of his to develop germs of living things, and says that he has learned from Dr. Koch, of Berlin, the use of gelatine in preserving the indications of organic vitality. About 2 ½ per cent of gelatine well heated in a little water is mixed with the water to be tested, and the mixture forms a transparent mass, which is not movable like the water itself. When soluble or unobserved matter develops from the organic matter of the water and makes itself visible in a solid and insoluble form, it does not fall to the bottom, but each active point shows around it the sphere of its activity, and that sphere is observed and remains long. The gelatine preserves the whole action, so far as the more striking results are concerned, and keeps a record, for a long time, both of the quality and intensity of life in the liquid.
Dr. Smith speaks at present of the more striking effects, which are clear and abundant, every little centre of life making itself clear to the eye and sometimes expanding its influence to reach both sides of the tube. It seems to him now essential that all chemical examination of water should be supplemented by an enquiry, like this of Dr. Kock’s, into this comparative activity of the living organisms.
The water must not have too much gelatine in it; if so, the action is stopped. It must not have too little; if so, the gelatine becomes liquid too soon, and the action of the individual centres is not observed. When a centre acts it makes around it a sphere in some waters, and the sphere which has the appearance of a thin vescicle [sic] is filled with liquid. These spheres form in a day or two, according to the water, and at the bottom is a white mass containing active bacteria chiefly.
The liquid filling the spheres may be taken out by a pipette and examined. As also the bacteria which lie at the bottom. He has not examined a sufficient number of waters to give general rules, but hopes to do so. He has as yet examined no chalk water for example, but has been confined chiefly to the Manchester district, hill water, impure brook and pond water, Mersey, Irwell, and Medlock water, and canal water. In certain specimens of Manchester supply the spheres appear on some days very few, on other days the amount is enormous and heavy, the whole of the tube in which the experiment is made is filled with spheres.
At such times the water is highly impure and complained of by the public. We have very easy proof, therefore, of the value of this test. The globules do not show themselves in strong sewer water, but the whole mass becomes turbid and the surface of the gelatine becomes liquid and full of life. This liquid condition gradually increases until the whole is reached. We have, therefore, two striking conditions well marked out.
A third may be said to exist, but it is often a mere beginning of the globules. This is shown by the formation of a small white opaque point. If this point is examined it is seen to be full of life like the lower part of the spheres and the fluid portion of the gelatine when this fluidity begins on the surface, He finds, also, that the solidity or fluidity of the gelatine is an important indication. This is known by the depth to which a certain weight will sink in it.
At present this mode of examining water seems to him to be far more important than the chemical, more decided and telling, but we cannot neglect the chemical. Dr. Smith describes the results of a series of tests, and says that the subject is being more fully developed under Dr. Koch and by Dr. Rozahegyi, and chemists must prepare for a new condition of things