Letter | Published:

Examination of Small Organisms in Water

Naturevolume 18page196 (1878) | Download Citation



IN order to examine the minute organisms that inhabit water, such as rotifers, vorticellæ, and kindred microzoons, the arrangement I proposed some years ago in the Quart. Journ. of Micros. Sci., will, I believe, be found most convenient. This is to inclose the objective in a brass or other metal tube having its lower end closed by a piece of thin microscopic glass coming close up to but not touching the object-glass. With this protection we can plunge the end of the microscope into a small tank, filled with water, containing the small living organisms, and examine them at our leisure for days or even weeks. The thin glass plate immersed in the water gives us a perfectly steady, flat water-surface, which is not disturbed by any agitation of the surface-water of the tank. Objectives of an inch, half an inch, a quarter of an inch, and even an eighth of an inch focus, may be thus used under water, and all the trouble of catching and ensnaring the small animals is thus avoided. This invention I first employed for the examination of morbid secretions, such as urine. I have since employed it for watching the operations of minute creatures that inhabit water, which may thus be seen in their natural habitat and under normal conditions, which is not the case when they are seen in the usual way, between the two layers of glass on an ordinary microscopic slide. Any optician can make such a tube to screw over the objective of any microscope, and, though it can readily be removed and applied, its presence does not interfere with the use of the microscope in air.

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  1. 53, Montagu Square, W.

    • R. E. DUDGEON


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