10 ' PROCEEDINGS OF THE ACADEMY OF 



must be cemented upon larger ones of the same kind if anything like trueism" 

 in the plane of the pection be attempted or required. 



Our si)ecimen exists, but is still unfit for mounting, because it is saturated 

 with oil and retains small particles of the putty. To rid it of'the latter it may 

 be removed to a slide by forceps, or, if too delicate, must be floated on the 

 water by tilting the vessel, and then dipped up on a slide. A camel's hair 

 pencil iuU of water readily washes away all particles of paper or dust, espe- 

 cially if the lamina be held upon the slide by the flattened end of a match 

 stick ; and the other surface, being made uppermost by turning in water, is 

 to be prepared in the same way. Once more drop the section in water ; then 

 with fine forceps remove and let it fall into the alcohol ; now transfer it to 

 chloroform ; and finally place it between bits of smooth bibulous paper, which 

 again lie between a couple of clean slides. A pair of spring forceps will 

 maintain flatness until the now finished section is required for mounting. 



After so much trouble it were a pity to lose a fine specimen by bad mount- 

 ing ; wherefore, and to prevent a loss of time and labor and much disap- 

 pointment, I beg leave to offer a few suggestions as to the manner of cageing 

 or embalming the result of our successful efforts. 



In any case choose the better side of the section as the uppermost, and 

 this is commonly the first. Have ready, for the dry method, a slide cleaned 

 with dilute alcohol, and upon it a shallow circle of shellac, applied in alco- 

 holic solution by the aid of the Shadbolt turn-table. The shellac should be 

 nearly hard after a day's exposure. Wipe the slide with dry cambric over 

 the circular area, and clean a suitable cover glass which has been lying in 

 dilute alcohol. Warm the slide over a flame of a spirit lamp to drive off 

 moisture ; suffer it to cool perfectly ; place the section in the cell ; warm and 

 cool the cover ; lay the latter upon the cell ; on the cover put a bit of thin 

 paper, and over this a piece of a slide, finally clamping all together by spring 

 forceps. The slide must be held over the spirit flame until the softened 

 shellac adheres all around the circle to the cover and the section is pressed 

 and held flat. 



When cold, the work is done. 



The embalming process, like the one just described, requires a little prac- 

 tice to ensure success. As soft balsam pervades almost all structure, it is 

 generally inapplicable to the mounting of tissues, such as bone and tooth. 

 At any rate I have already spoken of the manner of its use. But where 

 tubuli, &c., are to be made conspicuous by retained air, hardened, not hard, 

 balsam must be employed. 



To mount a section in such balsam I proceed as follows : On a slide free 

 from crocus-flaws pour a small quantity of so't balsam, and hold the same 

 over a spirit lamp until by vaporization the balsam shall have become tacky 

 when cold. The process is favored by tilting the slide to and fro. Let the 

 slide cool ; and ujion the end of a spatula blade prepare other balsam, but a 

 trifle less hard. The section being laid upon the cold balsam on the slide, 

 and this held between finger and thumb, the spatula blade is to be heated 

 until the balsam flows ; whereupon the blade is suddenly turned over and 

 made to press the hot cement upon the section for a moment. The heat strik- 

 ing through fixes the section ; and as the blade is withdrawn the slide must 

 instantly be held over the lamp until all the balsam melts. And here again 

 warpage is almost entirely prevented. 



At this moment the cover-glass, made warm, is laid over the specimen, not 

 flatly but dipping at one edge, and hy pressure is made to assume its proper 

 position. It almost always happens, however, that too much balsam is included 

 between the cover and the slide, and that air bubbles appear in the field. 

 To remedy these evils, I resort to a process similar t(j that which I employ 

 when fastening a cover-glass upon the shellac margin of a cell. I first cut 

 avvay all possible hard balsam with a hot knife-blade. Then, the slide being 

 cold, a strip of fine paper is laid over the whole of it, and upon the paper 

 another slide. The two plates of glass are presently to be clamped together 

 with stout forceps, closing with a slide, and, holding by the forceps, both of 



