140 ANATOMICAL TECHNOLOGY. 



B. Bltbe. — The plaster mass may be colored blue by cobalt or 

 ultramarine blue or a solution of anUine blue : Aniline blue, 2.5 

 grams ; 50 per cent, alcohol, 100 cc. 



0. Yellow or Green. — Employ chrome yellow or green. 



Permanent preparations should not be made of an animal in- 

 jected with a mass colored by one of the aniline dyes, for they are 

 soluble in alcohol and fade in the light. The vermilion and cobalt 

 blue are the most permanent, but the carmine and Berlin blue last 

 many years. 



§ 345. Prepeiration of Plaster Injection Masses. — The masses 

 should be used immediately after preparation, and before the plaster 

 has time to set. 



Approximately the same volume of plaster and liquid should be 

 employed for ordinary injections. If, however, one wishes the mass 

 to fill the smallest vessels, the liquid should be increased so that 

 the I'atio is as 1-2 or even 1-3. 



A. Mass Colored with Oarmine. — Measure out 100 cc. of the 

 finest plaster of Paris and put it into a mixing dish, a tea or coffee 

 cup, that will hold about 400 cc. Add to this plaster about 100 cc. 

 of the carmine solution (§ 343), and mix thoroughly with a wooden 

 or porcelain pestle. Finally, add slov/ly and with constant stirring 

 the 50 per cent, acetic acid. Add the acid till the color changes to 

 bright red and the odor of the acid in the mass is quite perceptible. 

 An excess of acid is less injurious than a deficiency. 



B. Mass Colored with Berlin Blue. — Plaster same as for car- 

 mine. Add 100 cc. of the Berlin blue solution (§ 343), and stir welL 

 No acid is necessary. 



C. Masses Stained with Aniline. — Measure out 100 cc. of plas- 

 ter and put it into the mixing dish as directed above ; then add, for 

 red, 20 cc. of the magenta solution and 100 cc. of the 15 per cent, 

 glycerin solution (§ 171). Stir thoroughly. For blue, add 50 cc. of 

 the blue aniline solution and 75 cc. of the 15 per cent, glycerin. 



D. Mass Colored with Vermilion or Bed Lead. — Put 25 grams 

 of the dry color into the mixing dish and add 25 cc. of 15 per cent, 

 glycerin. Grind the color thoroughly to crush all the lumps. 

 Finally, add 100 cc. of plaster and 100 cc. of 15 per cent, glycerin, 

 and mix very thoroughly. 



E. Masses Colored with Cobalt or Ultramarine Blue, Chrome 

 Yellow or Oreen. — Employ 15 cc. of tbe color, and prepare as 

 directed for the vermilion (§ 344). 



