1887.] MICROSCOPICAL JOURNAL. 93 
were kept in packs with a solid piece at top and bottom, and a rubber band 
to hold them. It soon became common to open one of the packs for a par- 
ticular slide and find it, with many others, destroyed by insects. To prevent 
the growth of mould, etc., the slides were kept in a box ina dry, warm 
closet ; this caused the paste, gum, or glue to crack, and often to pee! off the 
binding paper and labels, until I learned to add glycerin to the gum or glue ; 
then it never became entirely dry. 
My tribulations continued in this fashion until one spring, when house- 
cleaning invaded the premises, during which operation, unknown to me, 
some water was spilled upon my box of pasteboard slides. When the house 
was ‘settled’ again I found them a reeking mass of blue mould and all irre- 
trievably ruined, those that were covered as well as those that were not. I 
have never mounted a slide on pasteboard since. 
Pasteboard slides, even of heavy tarboard, bend so easily as to crack or 
loosen covers very easily, and unless well saturated with some resinous var- 
nish are liabie to mould on the slightest provocation, or to take up moisture 
from the air and deposit it under the cover. The material is so soft as to 
wear rough speedily in use, and covering with paper helps it but little to 
stand wear. Wooden slips are vastly better and can be cheaply made by 
boring a hole centrally edgewise through a piece of wood one inch thick and 
three inches long, of any width, and slitting it up on a saw table. If too 
thick they are clumsy, and if too thin are flimsy. 
For the class of objects named, for which low powers will ordinarily be 
sufficient, glass is the best material, and admits of examining both sides of 
the object. For objects that mast be viewed uncovered and on both sides, 
no other mount will equal two of Pierce’s capped cells mounted back to back 
with the object between, and fixed in a wooden slip, either temporarily or 
permanently, or on a metal plate. 
I venture the prediction that whoever uses cardboard for slides to any great 
extent will regret it. 
Gums and pastes for labels.—It is usually found that the addition of 
acetic or nitric acid to gums, glues, or pastes will make an efficient adhesive 
for almost any purpose. But, the following notes by Mr. L. Eliel, read before 
ne American Pharmaceutical Association, may be useful :— 
Gum tragacanth, I oz.; gum sui. 4 0z.; dissolve in water, I pt.; 
Me and add thymol, 14 grains, suspended in glycerin, 4 oz.; finally add 
water to make 2 pints. This makes a thin paste, suitable for labeling bot- 
tles or wooden or tin boxes, or any other purpose for which paste is liable to 
be required. It will keep sweet indefinitely, the thymol preventing fermen- 
tation, and though it separates on See, a single shake will mix it sufh- 
ciently for use. 
2. Rye flour, 4 oz. ; powdered acacia, $ oz. ; rub toa smooth paste with8 oz. 
of cold water; strain through a cheese-cloth and pour into one pint of cold 
water; heat until thickened. to suit. When cold add glycerin, 1 oz. ; oil of 
cloves, 20 drops. This is suitable for adhesion on tin, wood, or glass, and 
keeps sweet a long time. 
3. Rye flour, 4 0oz.; water, 1 pt.; nitric acid, 1 drm.; carbolic acid, ro 
min.; oil of cloves, 10 min.; glycerin, 1 oz. Mix the flour with the water, 
strain through a cheese cloth, and add nitric acid. Heat till thickened to 
suit, and add other ingredients when cooling. 
4. Dextrine, 8 parts ; acetic acid, 2 parts ; alcohol, 2 parts ; water, 10 parts ; 
mix dextrine, water, and acetic acid to a smooth paste, then add the alcohol. 
It makes a thin paste suitable for wood or glass, but will not adhere to tin.— 
English Mechanic, Feb. 18, 1887. 
