140 ANATOMICAL TECHNOLOGY. 



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

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

 grams ; 50 per cent, alcohol, 100 cc. 



O. Yellow or Green. — Employ ciirome 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. Preparation of Plaster Injection Masses. — The masses 

 should be used immediately after preparation, and before the jjlaster 

 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 ratio is as 1-2 or even 1-3. 



A. Mass Colored loith Carmine. — 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 slowly and with constant stirring 

 the 60 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 jjer 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 Red 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 

 Yelloio or Green. — Employ 15 cc. of the color, and prepare as 

 directed for the vermilion (§ 344). 



