Microscopical morphology of the animal body in health and disease / by C. Heitzmann. With 380 original engravings.
- Carl Heitzmann
- Date:
- 1883
Licence: Public Domain Mark
Credit: Microscopical morphology of the animal body in health and disease / by C. Heitzmann. With 380 original engravings. Source: Wellcome Collection.
Provider: This material has been provided by the Augustus C. Long Health Sciences Library at Columbia University and Columbia University Libraries/Information Services, through the Medical Heritage Library. The original may be consulted at the the Augustus C. Long Health Sciences Library at Columbia University and Columbia University.
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![filtering-paper; a dro]) of dilute glycerine is added—best with the glass stem of the hottlc liolding glycerine — to the specimen, which is then worked down to the center of a glass slide. Here the specimen is spread out, if necessary, with two needles, its position corrected, and the covering-glass gently placed over the drop, so as to avoid including aii--l)ul)])les. With a little pra(;tice and skill we learn to add the exact quantity of glycerine. Should the drop prove to he too small,—\t.z., if a (corner or edge of the covering-glass wants glycerine,— a small droplet is approached to that edge, and will flow under by capillary attraction. If too much glycerine be taken, it must be drained off l)y moist flltering-paper, and the slide cleansed carefully with a j)iece of such paper folded up and moistened. The sealing together of both glasses should be accomplished by painting varnish in the shape of a narrow but heavy rim along the edge of the covering-glass; but great care must be taken to have both slide and cover first absolutely clean and dry. The only liquid which can be fully recommended for mount- ing hardened specimens is glycerine in the purest chemical condition, to which distilled water (aljout one part of water to three parts of glycerine) is added. Mounting in Canada balsam or in damar varnish is objectionable, as the specimens in these liquids in time clear up to such an extent as to become unfit for ampHflcations of the microscope exceeding 300 or 500 diameters. Long-continued trials, as regards the value of both methods, have led me to this conviction. Specimens of any description, mounted in Canada balsam or in damar varnish, are not suitable as test objects. To-day, the power of definition of a lens shoidd be tested exclusively on living objects, such as infusion organ- isms, fresh blood corpuscles, saliva corpuscles, etc. The process of mounting in glycerine is simpler and easier than any other method, and, if all precautions mentioned are carried out with care, no change of the specimen will take place. True, glycerine specimens need more careful handling than balsam specimens, but their value is decidedly greater than that of the latter. In order to make glycerine mounting safe, it is preferable to delay applying the varnish for twenty-four hours, as the surplus water by that time will have evaporated. Should too little glycerine be used, the inclosing varnish will run under the cover and deprive the specimen of its neat appearance; shoidd too much glycerine be left between the two glasses, it often happens that after months or years the glycerine finds its way through](https://iiif.wellcomecollection.org/image/b21219163_0034.jp2/full/800%2C/0/default.jpg)
