RANVIER'S CARMINE-GELATIN MASS. 261 



464. Scheele's Green Colouring Mass (ibid., p. 37). 

 Take- 



Arseniate of potash (saturated solution) 80 c.c. 



Glycerin . . . . . 50 



and 



Sulphate of copper (saturated solution) 40 



Glycerin . . . . . 50 ,, 



Mix and combine with 3 vols. of vehicle. 



465. Anilin Colouring Masses (ibid., p. 37). Most of the 

 anilin colours have, for injections, the great fault of being 

 soluble in alcohol ; fuchsin is soluble in water, in alcohol, and 

 in glycerin ; it therefore cannot be employed with a gelatin 

 or glycerin vehicle. Anilin blue, violet, yellow, may be com- 

 bined with these vehicles after dissolving in a small quantity 

 of alcohol; and (alcohol being avoided for hardening purposes) 

 the injected organs may be preserved in glycerin. 



Carmine-Gelatin Masses. 



466. Ranvier's Carmine-Gelatin Mass (Traite technique , p. 

 116). Take 5 grms. Paris gelatin, soak it in water for half 

 an hour, or until quite swollen and soft ; wash it ; drain it ; 

 put it into a test-tube atod melt it, in the water it has absorbed, 

 over a water-bath. When melted add slowly, and with con- 

 tinual agitation, a solution of carmine in ammonia, prepared 

 as follows : 2J grms. of carmine are rubbed up with a little 

 water, and just enough ammonia, added drop by drop, to dis- 

 solve the carmine into a transparent solution. 



When the carmine has been added to the gelatin you will 

 have about 15 c.c. of ammoniacal solution of carmine in 

 gelatin, if the operations have been properly performed. This 

 solution is to be kept warm on the water-bath, whilst you 

 proceed to neutralise it by adding cautiously, drop by drop, 

 with continual agitation, a solution of 1 part of glacial acetic 

 acid in. 2 parts of water. (When the mass is near neutrality, 

 dilute the acetic acid still further.) The instant of saturation 

 is determined by the smell of the solution, which gradually 

 changes from ammoniacal to sour. As soon as the sour smell 

 is perceived, the addition of acetic acid must cease, and the 

 liquid be examined under the microscope. If it contains a 



