150 



THE AMERICAN MONTHLY 



[August, 



h. Invert the cover of a pill-box 

 and lay the slide upon it, then place 

 a large drop of the preservative 

 within the cell, and cause it to flow 

 so as to touch every part of the cell. 

 Transfer the objisct to the slide and 

 arrange it properly by means of 

 needles. 



c. Take a mounted needle in the 

 left-hand, and in the right the cover 

 in a pair of forceps. Place the 

 needle-point on the cell on the left- 

 hand side, and place the edge of 

 the cover against it on the cell ; 

 then let the cover down slowly, so 

 as to disarrange the object as little 

 as possible, breathing upon the 

 lower surface, so that the fluid may 

 readily come in contact with it. 

 When the cover is down, press it 

 into the still soft balsam, but apply 

 the pressure only around the out- 

 side ; otherwise too much fluid is 

 likely to be forced out, and a bubble 

 of air will enter when the pressure 

 is removed. Let the slide stand for 

 a few minutes, then wash it carefully 

 by a gentle current of water from a 

 tap or sponge, and set it aside to 

 dry. 



d. When dry, run a circle of ben- 

 zole-balsam around it, after which 

 the slide can be set aside for months, 

 before the finishing process is car- 

 ried out. In this condition the object 

 will keep for any length of time if 

 undisturbed, but after a while the 

 balsam becomes very brittle, .so that 

 a more elastic cement is required to 

 protect the slide from the effects of 

 rough usage. We are accustomed 

 to set the slides away immediately 

 after the last layer of balsam is ap- 

 plied until a number have accumu- 

 lated to undergo the finishing oper- 

 ations together. 



e. Finish the slides by applying 

 several coats of the mixture of as- 

 phalt and gold-size, followed by a 

 final coat of plain asphalt to give a 

 glossy black. 



The above process will suffice for 

 mounts in strong glycerin. Many 

 mounters have discarded glycerin as 

 mounting medinm because they have 

 failed to find a cement that will re- 

 tain the glycerin. They have tried 

 shellac, but it has failed them. Now, 

 we speak from considerable expe- 

 rience witli glycerin as a mounting 

 medium, and we do not hesitate to 

 assert that shellac will make a per- 

 fectly tight and impervious cell for 

 a glycerin mount, and we prefer to 

 use shellac instead of the benzole- 

 balsam for mounting with strong 

 glycerin. The secret of success 

 seems to be in washing off every 

 trace of the glycerin, before the se- 

 cond coat of shellac is applied. 



Microscopists are indebted to Mr. 

 C. Van Br nut, of New York, for 

 the process of cementing the cover 

 with benzole-balsam and gold-size 

 and asphalt. 



Improvement in Making Wax- 

 cells. 



BY JOHN D. WHITE. 



For making wax-cells when they 

 are wanted smoother and handsomer 

 than they can be made with a punch 

 alone, I recommend the following 

 process as simpler and easier than 

 that of Dr. Hamlin, described on 

 page 46. With home-made punches 

 of ordinary brass tubing (cartridge- 

 cases answer very well), cutout rings 

 and disks a little larger than the 

 finished cells are to be, and fasten 

 them to the slides by pressure and 

 gentle warmth, after centering as 

 accurately as possible. Then, with 

 a tool made by bending a small 

 chisel at a right-angle about half 

 an inch from the edge, turn or scrape 

 the cell on a turn-table until it is of 

 the right size. If the tool is sharp, 

 a beautifully polished surface will 

 always result. The chisels which 

 accompany sets of brad-awls are 



