INVERTEBEATA, CRYPTOGAMIA, MICROSCOPY, ETC. 859 



The advtantagos claimed for this process are that objects need 

 never be allowed to dry before mounting in balsam or dammar ; that 

 the operation from first to last is simple and cleanly ; while compared 

 with the old turpentine process, this is wonderfully rapid. A tiny 

 insect may bo caught alive, boiled, cleared, mounted in balsam, the 

 slide finished oft" and put away in the cabinet, all within half an hour. 



Objects saturated with water should be drained as well as possible, 

 without allowing all the water to run off, as in that case air might be 

 admitted, then transferred to a clean test-tube, covered with carbolic 

 acid from the working bottle, and boiled for a few minutes over a 

 spirit-lamp. Corked tightly, a test-tube full of objects in acid may 

 be put asido for any length of time before mounting. When we 

 desire to mount one of these objects we transfer it to a clean slide, 

 put on a thin glass cover, and with the aid of a small pipette allow 

 enough clean carbolic acid to run in to flood the object. Having 

 examined under the Microscope, and arranged it to our liking, we 

 warm the slide over a spirit-lamp, and place sufficient balsam or 

 dammar on the slide close to the cover ; liquefied by the heat either 

 medium will at once rim in and drive the acid out at the other side. 

 This will be greatly facilitated by inclining the slide and holding a 

 small piece of blotting paper under the thumb close to the lower edge 

 of the thin cover. When all the acid has been drawn off, the slide is 

 then placed on a hot-plate to harden, and afterwards finished in the 

 usual manner by scraping off the superfluous balsam, wiping the slide 

 carefully with a clean rag moistened with spirits of wine, and finished 

 on the turntable by sealing the cover with a ring of Brunswick 

 black or other varnish. 



Another aid to the thorough displacement of the acid is to use the 

 balsam in as thick and pasty a condition as possible. At the same 

 time this is not essential to success, as thin balsam works very well. 

 Benzine* should bo used in preference to turpentine to liquefy 

 balsam that has become too stiff. Newly purchased balsam is often 

 very thin. In this case it is advisable to bake it in a cool oven for 

 some days until it is hard enough to resist slight pressure, and then 

 add about one-fourth part of benzine, placing the bottle in a hot- 

 water bath, which will ensure perfect mixture. Balsam thus prepared 

 will harden quickly, which it does not do if liquefied by turpentine. 

 Turpentine may therefore bo excluded from the Microscopist's 

 laboratory. 



When mounting, it is well to bo provided with several pieces of 

 blotting paper about an inch square. These should bo used as above 

 described to aid tlie substitution of one licpiid for another, particularly 

 when displacing watery carbolic acid by pure acid. 



Vegetable tissues such as plant leaves, sections of wood, &.C., after 

 washing in water may be drained and transferred at once to tlie slide, 

 covered by thin glass, flooded in carbolic acid, and then boiled over 

 the spirit-lamp, adding fresli acid from time to time until tlie object 

 is perfectly clear. Air bubbles may thus bo boiled t)ut, and the 



* Some prcfur chlornfonn, wliicli will lic|Uefy \hv ))iilsam willioiit luat, but wo 

 tliiuk the Ijcnzino mucli superior in aubaoquciit opcrutious. 



