236 INJECTION GELATIN MASSES (WARM). 



washed, treated for a short time with hydrochloric acid of 2 per cent., 

 washed, melted and preserved with camphor. 



484. Other Carmine- Gelatin Masses. THIERSCH'S, see Arch. mik. 

 AnaL, 1865, p. 148. GERLACH'S, see RANVIER, Traite, p. 118, CARTER'S, 

 see BEALE, p. 113. DAVIES, see his Prep, and Mounting of Mic. Objects, 

 p. 138. 



Blue Gelatin Masses. 



485. KANVIER'S Prussian Blue Gelatin Mass (Traite, p. 119). 

 Make a concentrated solution of sulphate of peroxide of iron in 

 distilled water, and pour it gradually into a concentrated solution 

 of yellow prussiate of potash. There is produced a precipitate of 

 insoluble Prussian blue. Wash this on a felt strainer, underneath 

 which is arranged a paper filter in a glass funnel, for some days, 

 until the liquid begins to run off blue from the second filter. The 

 Prussian blue has now become soluble. The strainer is turned 

 inside out and agitated in distilled water ; the Prussian blue will 

 dissolve if the quantity of water be sufficient. 



The solution may now be injected just as it is, or it may be kept 

 in bottles till wanted, or evaporated in a stove, and the solid 

 residuum put away in bottle. 



For injections, if a simple aqueous solution be taken, it should be 

 saturated. Such a mass never transudes though the walls of 

 vessels. Or it may be combined with one-fourth of glycerin, or 

 with one twenty-fifth of gelatin soaked for an hour in water and 

 melted over a water-bath in the water it has absorbed. The gelatin 

 is to be poured gradually into the Prussian blue, on the water-bath, 

 stirring continually until the curdy precipitate that forms at first 

 has disappeared. Filter through new flannel and keep at 40 C. 

 until injected. 



486. BRUCKE'S Soluble Berlin Blue (Arch. mik. Anat., 1865, p. 87). 

 Make a solution of ferrocyanide of potassium containing 217 grins, of 

 the salt to 1 litre of water, and one of 1 part commercial chloride of iron 

 in 10 parts water. Take equal volumes of each, and add to each of 

 them twice its volume of a cold saturated solution of sulphate of soda. 

 Pour the chloride solution into the ferrocyanide solution, stirring con- 

 tinually. Wash the precipitate on a filter until soluble, dry it, press 

 between blotting paper in a press, break the mass in pieces, and dry in 

 the air. 



The concentrated solution of the colouring matter is to be gelatinised 

 with just so much gelatin that the mass forms a jelly when cold. For 

 another method, see previous editions. 



487. Other Blue Gelatin Masses. HOYER'S, Arch. mik. Anat., 1876, 

 p. 649 ; GUIGNET'S, Journ. de Microgr., 1889, p. 94 ; Journ. Roy. Mic. 



