Directions for making and preserving microscopical preparations / by Harting of Utrecht.

Date:
[1852]
Catalogue details

Licence: Public Domain Mark

Credit: Directions for making and preserving microscopical preparations / by Harting of Utrecht. Source: Wellcome Collection.

Provider: This material has been provided by the Royal College of Physicians of Edinburgh. The original may be consulted at the Royal College of Physicians of Edinburgh.

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    plicable to blood-corpuscles, which can be preserved unaltered in no other fluid with which I have experimented. Thus the blood-corpuscles of the frog require a fluid containing 4^)T)th of corrosive muriate; those of birds a solution of ^-Lyth ; those of mammalia and man South. These solutions are likewise useful for keeping the elementary parts of the brain, spinal cord, and retina, although all these structures, in whatever fluid they are put up, undergo some alteration. Cartilage, and the fibres of the crys- talline lens, keep well in these fluids; but other fibrous tissues lose too much of their transparency when in contact with them. They may be used, however, for preserving muscular fibre, whose cross markings they render more distinct. For preparations of delicate vegetable tissues, and, in general, of all tender organs in which it is desired to retain the starch globules and chlorophyl unaltered, for fresh water alga?, diatomacete, confervte, infusoria belonging to the division rotifera, &c., a solution containing ?foth or ^fojtli of corrosive sublimate is the best preservative with which I am acquainted. VI.—Solution of Carbonate of Potass. This may be made of various strengths, with one part of the salt dissolved in from 200 to 500 parts of water, and is the best material for preserving the pri- mitive nerve tubes. Other fibrous tissues may be kept tolerably well in it, but become more transparent than in the fresh condition. This is sometimes advan- tageous, as, for example, when we wish to display the respiratory apparatus of insects with the ramifications of the air-tubes. VII.—Solution of Arsenite of Potass. I have, in a few instances, made use of a solution of arsenite of potass in 160 parts of water, to preserve the primitive nerve-tubes. It has been found as effectual as the carbonate of potass solution. In employing the chloride of calcium solution1 and Canada Balsam, it is un- necessary to take measures to prevent the evaporation of the fluid. The first remains always fluid,— chloride of calcium being a deliquescent salt; and as the outer surface of the balsam hardens, the escape of the liquid portion is prevented. But it is otherwise with the last-mentioned preservative fluids (Nos. III. to VII.) To prevent their evaporation, it is necessary to employ a cement or luting to prevent air from having access to the fluid. Different compositions have been recommended for this purpose; but I have found none more serviceable than that employed by gilders to make gold-leaf adhere to mirror and picture frames. The following is the receipt for the preparation of this so-called gold- ground or gold-size:— Let twenty-five parts of linseed oil be boiled for three hours with one part of 1 The author has renounced the practice of putting up preparations in this fluid, and permitting the access of air, for reasons given at p. 2, line 29. et seq.—[Trans.]