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Jnjecting Small animale for fIDlcroecopical 



purpoaee. 



By R. N. Reynolds, M.D., Detroit, Mich. 



HAVING experienced much disappointment in the results of 

 injections with injecting gelatin purchased, I experi- 

 mented until I found proportions of the materials which 

 would give uniform, beautiful specimens, and at less than half the 

 cost of the old method. For thirteen ounces of gelatin costing 

 about fifty cents., which would be sufficient for a full-grown cat, 

 take of gelatin (such as is sold in checkered packages in grocery 

 stores) 600 grains, place in a pint fruit-jar and add to it five ounces 

 of cold water ; cover, and set aside for an hour or over-night. Put 

 into another air-tight jar, (No. 40) carmine, 400 grains; water, 4 oz. ; 

 and stronger water of ammonia {amvionia fort.), 4 drams. 

 Cover tightly and set aside. 



When ready to proceed, place the jar of gelatin into a water- 

 bath and heat until the gelatin is melted ; then strain through a 

 fine cloth into a clean jar (a linen handkerchief makes a good 

 strainer). Next insert a wad of absorbent cotton into the neck of 

 the funnel, and through it filter the carmine solution into a jar of 

 gelatin which has been kept warm in the water-bath. If the 

 cotton plug proves too tight to allow all the carmine to pass 

 through, decant the remainder into the jar it came from, replacing 

 the cotton plug by a looser one. 



After all the carmine has passed through into the gelatin, 

 clean the funnel, and place in it a fresh plug of cotton, pour into 

 the funnel some water, and with a rod press down the cotton until 

 the water goes through drop by drop. This test ivater is ?iot to be 

 allowed to drop into the gelatin. Then replace the funnel so that 

 it hangs over the gelatin, putting into the funnel the following to 

 granulate the carmine : — Water, 2 oz. ; glacial acetic acid, 4 drs. ; 

 and while this is dropping in, the gelatin must be continuously 

 stirred. By the time the whole of the acid has passed in, the 

 gelatin will be changed from a dark lilac to a bright scarlet 

 colour, and is then ready for use. 



The exact quantity of acid that it will take to bring about this 



