The microscope and microscopical methods / by Simon Henry Gage...and illustrated by 165 text figures in the text.

  • Gage, Simon Henry, 1851-1944.
Date:
1896
Catalogue details

Licence: Public Domain Mark

Credit: The microscope and microscopical methods / by Simon Henry Gage...and illustrated by 165 text figures in the text. Source: Wellcome Collection.

Provider: This material has been provided by the Harvey Cushing/John Hay Whitney Medical Library at Yale University, through the Medical Heritage Library. The original may be consulted at the Harvey Cushing/John Hay Whitney Medical Library at Yale University.

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    The xylene is much the best substance to use for thinning the balsam. Such xylene balsam, as it is then called, may be nseil for mounting any object suitable for balsam mounting. The dehydration must be very perfect, however, as xylene is wholly immiscible with water. Natural balsam is liable to be slightly acid. This is of advantage for mounting sections stained with carmine or injected with carmin gelatin or Berlin blue gela- tin. For hematoxylin preparations and for fuchsin preparations the acid will cause the color to fade. The balsam may be neutralized by mixing some carbonate of soda with the thinned solution before it is thickened. In a few days all the soda will settle and the clear balsam above will be neutral and may be poured off and thickened. If one mounts carmine or Berlin blue preparations in the neutral bal- sam the blue will fade and the carmine diffuse. I 301. Chloroform Paraffin.—This is made by mixing the 4 parts of the paraffin used for imbedding (? 314) with 1 part of chloroform. This gives a paraffin which melts at a lower temperature than the pure paraffin. If it is kept warm the chloro- form evaporates in 3 to 6 days, leaving pure paraffin. \ 302. Clanfler, Castor-Xylene Clanfier.—This is composed of castor oil 1 part and xylene* 3 parts. (1 303. Clearing Mixture (<1 266. 2S2). — (A). One of the most satisfactory and generally applicable clearers is carbol turpentine, made by mixing carbolic acid crystals (Acidum carbolicum. A. phenicum crystal?'zatum) 40 cc. with rectified oil of turpentine (Oleum terebinthinae rectificatum) 60 cc. If the carbolic acid does not dissolve in the turpentine add 5 cc. of 95% alcohol, or increase the tur- pentine, thus : carbolic acid 30 cc, turpentir.e 70 cc. (B). Carbol-Xylene, Clearer.—Vasale recommends as a clearer, xylene 75 cc, carbolic acid (melted crystals) 23 cc. It is used in the same way as the preceding. \ 304. CollodiDn.—This is a solution of soluble cottonf or other form of pyroxy- lin in equal parts of sulphuric ether and 93% alcohol. Three solutions are used : *The hydrocarbon xylene (C3H,J is called xylol in German. In English, members of the hydrocarbon series have the termination ene while members of the alcohol series terminate in ol. fTlie substance used in preparing collodion goes by various names, soluble cot- ton or collodion cotton is perhaps best. This is cellulose nitrate, and consists of => mixture of cellulose tetranitrate CIa Hl6 (N03)4 06, and cellulose pentanitrale, C„ H,5 (N03); 05. Besides the names soluble and collodion cotton, it is called gun cotton and pyroxylin. Pyroxylin is the more general term and includes several of the cellulose nitrates. Celloidin is a patent preparation of pyroxylin, more ex- pensive than soluble cotton, but in no way superior to it for imbedding. Soluble cotton should be kept in the dark to avoid decomposition. After it is in solution this decomposition is not so liable to occur. The decomposition of the dry cotton gives rise to nitrous acid, and hence it is best to keep it in a box loosely covered so that the nitrous acid may escape. Cellulose nitrate is explosive under concussion and when heated to 1500 centi- grade. In the air, the loose soluble cotton burns without explosion. It is said not to injure the hand if held upon it during ignition and that it does not fire gun- powder if burned upon it. So far as known to the writer, no accident has ever occurred from the use of soluble cotton for microscopical purposes. I wish to ex- press my thanks to Professor W. R. Orudorff, organic chemist in Cornell Univer- sity, for the above information. Proc. Amer. Micr. Soc, vol. XVII (189;,), pp. lt>\-},io.