FORMULAE. 199 



This is an excellent cement for glycerin mounts. It should be 

 considerably thinned for use as a vehicle for color. 



PRESERVATIVE FLUID. 



Acetate of Soda, 1 Ib. 



Distilled Water, 8 ounces. 



Scraping or teasings from tissues, morphological elements from 

 urinary sediment, casts, in fact, almost any histological element may 

 be indefinitely preserved in this solution. It is important that the 

 tissues, etc., be freed from organic matters in solution, before being 

 placed in the preservative; for example: urine must be carefully 

 decanted from the sediment to be preserved before the acetate solu- 

 tion is added. I am enabled to preserve the different forms of cells 

 from year to year, for my classes, in small bottles of this fluid. When 

 a demonstration is required, it is simply necessary to transfer a drop 

 of the sediment, by means of a pipette, to a slide, and apply the 

 cover-glass. , 



If it be desired to preserve such a mount, wipe the edges of the 

 cover with a bit of blotting paper, and seal with a ring of shellac 

 or asphalt um varnish, or zinc cement, applied with a small brush. 



NORMAL SALT SOLUTION. 



Chloride of Sodium (common salt), . * 7 grains. 

 Distilled Water, 2 fluidounces. 



A medium for the temporary examination of fresh tissues scrap- 

 ings, teasings, etc. 



RAZOR-STROP PASTE. 



Sulphate of iron and common salt equal parts. Calcine in a sand 

 crucible at a dull red heat for ten minutes. When cold, grind lightly 

 in a porcelain mortar and pass through fine gauze. Preserve dry in a 

 well-corked bottle. 



A few grains dusted on the surface and mixed with a minute quan- 

 tity of tallow will add greatly to the efficiency of the strop. 



Another. Equal parts of opticians' rouge and the finest washed 

 flour of emery, mixed with a sufficient quantity of vaseline to make a 

 stiff paste. 



