Microscopical and General Scientific Society
At a meeting in the Grammar School on Wednesday evening, March 8th, Dr. Mitchell Wilson in the chair, a paper on Diatoms was read by Mr. J.M. Kirk.
Twenty-nine members were present.
Diatoms have long been considered to be the remains of animalcules and most of the older microscopical books treat them as such. Although the question is far from being settled, it is now general to consider them as belonging to the vegetable kingdom. Diatoms, like Desmids, are simple cells having a firm outer coating, within which is enclosed in an additional one. The Diatomaceae are divided into two chief groups – Those which are single frustules and those which colure in masses.
The name seems to have been given to them from the readiness with which the latter may be cut, or broken through; hence they are some times called “brittle worts”. During the healthy life of a Diatom, the process of self-division is continually being repeated, and a very rapid multiplication of frustules takes place, all of which are repetitions of the same individual form. These original forms are of great variety.
A large part of the ‘infusorial earths’ deposited at the bottom of lakes is composed of diatoms, one such remarkable deposit being the tripoil or rotten stone, used for polishing metals. The well known Turkey Stone, and the material called “Silicon” now sold for polishing plate, is similarly composed. Such is the abundance of diatoms in some rivers and estuaries, that their multiplication is affirmed by Ehrenberg to have exercised an important influence in blocking up harbours and diminishing the depth of channels.
It is remarked by Hooker that the universal presence of this invisible vegetation throughout the South Polar Ocean is a most important feature, since there is a marked deficiency in this region of higher forms of vegetation, and were it not for them, there would be neither food for aquatic animals, nor (if it were possible for these to maintain themselves by preying on one another) could the ocean waters be purified of the carbonic acid which animal respiration and decomposition would be continually imparting to them. A diatomaceous deposit exists in Norway & Sweden, under the name of “Berg mahl” or mountain flour; and in times of scarcity the inhabitants mix this with their dough in making bread.
Mr. Kirk explained the method for collecting, preserving & mounting the various diatoms, and illustrated his paper by a large number of beautifully executed drawings of typical forms, among the more elaborate of which may be mentioned the representations of Arachnoidiscus, Heliopelta, and Isthmia.
A discussion followed, after which a vote of thanks to Mr. Kirk was proposed by Mr. Selby, and seconded by the Rev. George Smith; and the meeting resolved itself into a conversazione, many microscopes being exhibited showing specimens of diatoms.
[Doncaster Gazette, 17 March 1882]
For more information regarding the modern preparation of Diatoms for the microscope, see here