. The botanist's companion; or, Directions for the use of the microscope. Botany; Microscopy. 30 PREPARATION OF CELLS. quired; the thin glass is applied at once to the slide, a drop or two of the fluid being inserted along with the specimen. In the case of some dry preparations, as pollen-grains, and the fine-lined Diatoms, no fluid what- ever is required, but precautions must be taken against the access of damp. Canada balsam is useful in some instances. The specimen is put on a slide, then a minute portion of the balsam is put above it, and the thin glass above all; the slide is heated gentl
. The botanist's companion; or, Directions for the use of the microscope. Botany; Microscopy. 30 PREPARATION OF CELLS. quired; the thin glass is applied at once to the slide, a drop or two of the fluid being inserted along with the specimen. In the case of some dry preparations, as pollen-grains, and the fine-lined Diatoms, no fluid what- ever is required, but precautions must be taken against the access of damp. Canada balsam is useful in some instances. The specimen is put on a slide, then a minute portion of the balsam is put above it, and the thin glass above all; the slide is heated gently below by means of a spirit lamp until the balsam be- comes quite fluid, and until all the air has been expelled by the weight of the glass cover. It is then set aside to dry, and ultimately a rim of asphalte is put round the margin of the glass cover. Canada balsam is well fitted for many Diatoms, and for thin sections of woods. In putting up woods, the specimen is placed in the centre of the glass, a drop of turpentine is put Fig. 18. on it to expel the air, Canada balsam is then applied before the turpentine dries, and the same procedure is followed as above. On preparing fossils for microscopic examination, Mr. Alexander Bryson remarks :*— The usual mode of proceeding in making a section of fossil wood is simple, though tedious. The first process is to flatten the specimen to be operated on by grinding it on a flat lap made of lead charged with emery or corundum powder. It must now be rendered perfectly flat by hand on a plate of metal or glass, using much finer emery than in the first operation of grinding. The next operation is to cement the. Fig. 18. Apparatus for aiding in making the circular rim of asphalte; 5, a piece of mahogany; a, a circular piece of brass, which can be moved round by the hand, and has two brass springs on its surface for holding a glass slide firm. In the centre of the brass disc are circular markings fitted for the size of asphalte cells requi
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Keywords: ., bookcentury1800, bookde, booksubjectbotany, booksubjectmicroscopy
