A companion to the United States pharmacopia; . as possible with a sharp knife,and lay it into a small quantity of strong solution ofcaustic potassa, contained in a watch-glass, and allowit to macerate for a few minutes to half an hour, bywhich time most of the coloring matter and cell con-tents will have been dissolved. We can then wash itin a few changes of water, and, if not clear enough, ina little solution of chlorinated soda. The section isthen soaked for a few moments in glycerin, transferredto a slip of clear glass, covered with a drop of glycerinand a thin cover-glass in such a manner
A companion to the United States pharmacopia; . as possible with a sharp knife,and lay it into a small quantity of strong solution ofcaustic potassa, contained in a watch-glass, and allowit to macerate for a few minutes to half an hour, bywhich time most of the coloring matter and cell con-tents will have been dissolved. We can then wash itin a few changes of water, and, if not clear enough, ina little solution of chlorinated soda. The section isthen soaked for a few moments in glycerin, transferredto a slip of clear glass, covered with a drop of glycerinand a thin cover-glass in such a manner that as fewair-bubbles as possible may remain. It is then ready Fig. 558.— Codding- . .,, ,, T ton Lens, for examination with the microscope, in many cases even this is not necessary, and the section may be placed at once in a drop of water, glycerin, or solution of potassa on the slide and covered with the cover-glass, but the result will not be as satisfactory as when treated as above. This seems to be difficult and to require much time,. UNITED STATES PHARMACOPEIA. 1047 but the actual time consumed in the various steps of the proceedingneed not occupy more than two or three minutes, the time while wait-ing for the maceration of the section being of course available for otherwork. Powdered drugs may be moistened with turpentine and placed on aslide and covered, when they are ready for examination ; starches, how-ever, are rendered so transparent by this means that they can only beseen by aid of the polariscope. Or the powder may be moistened withsolution of caustic potassa, and placed on the glass slip and covered,but must be examined at once, as starches are soon dissolved. Powders in alcohol, glycerin, turpentine, or water, will often revealthe ingredients very nicely, and a little practice will soon enable oneto judge pretty well what medium will prove best in each individualcase. But if we wish to preserve the specimens for future reference andstudy, the process of pre
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