INJECTION- -GELATIN MASSES (WAHRl). 261 



get the mass ready for use, the strips are soaked for an hour 

 in water, and melted on a water-bath in 10 to 20 parts of 

 water. 



For another process, which is said to give somewhat better results, 

 but is more complicated, see loc. cit., or Zeit. wiss. Zool., xxxviii, p. 492, 

 or previous editions. 



491. KRAUSE'S Carmine-Gelatin Mass (Zeit. wiss. Milt., xxvi, 1909, 

 p. 1). 100 grins, gelatin soaked in water, put for two to three days into 

 a solution of 15 grms. carmine in 2 litres of water with 100 grms. of borax, 

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

 washed, melted and preserved with camphor. 



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

 Anat., 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. 



493. ROBIN'S Prussian Blue Gelatin Mass (see 486). 



494. RANVIER'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 concen- 

 trated 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 through 

 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 



