INJECTION 237 



gelatin is to be poured frradually into tlie Prussian blue, on the 

 water-bath, stirring eontinually \uitil the eurdy preeipitate that 

 forms at first has disappeared. Filter through new llanncl and 

 keep at 40° C. until injeeted. 



529. Brucke's Soluble Berlin Blue {Arch. niik. Anat., 1865, p. 87). 

 Make a sokition of ferrocyanide of potassium containing 217 grni. 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. 



530. Other Blue Gelatin Masses. Hoyer's, Arch. niik. Anat., 1876, 

 p. 649 ; Guignet's, Journ. de Microgr., 1889, p. 94 ; Joiirn. Roy. Mic. 

 Soc, 1889, p. 463 ; Thiersch's, Arch. mik. Anat., i, 1865, p. 148 ; Fol's, 

 Zeit. wiss. Zool., xxxviii, 1883, p. 494 ; and inevious editions. 



OTHER COLOURS 



531. Hoyer's Silver Nitrate Yellow Gelatin Mass {Biol. Centralb., 

 ii, 1882, pp. 19, 22). A concentrated solution of gelatin is mixed 

 with an equal volume of a 4 per cent, solution of nitrate of silver 

 and warmed. To this is added a very small quantity of an aqueous 

 solution of pyrogallic acid, which reduces the silver in a few 

 seconds ; chloral and glycerin are added as directed § 524. 



This mass is yellow in the capillaries and brown in the larger 

 vessels. 



532. Other Colours. Hoyer's Green {Biol. Centralb., ii, 1882, p. 19), 

 Made by mixing a blue mass and a yellow mass. Thiersch's Green 

 {Arch. mik. Anat., 1865, p. 149). Robin's Scheele's Green (Robin, 

 Traite, p. 37). Harting's White (see Frey, Le Microscope, p. 190). 

 Frey's White {ibid.). Teichmann's White {ibid., p. 191). Fol's 

 Brown {Zeit. iviss. Zool., xxxviii, 1883, p. 494). Miller's Purple (see 

 Amer. Mon. Mic. Journ., 1888, p. 50 ; Journ. Roy. Mic. Soc, 1888, 

 p. 518). Fol's Lead Chromate {Lehrb., p. 15). Robin's Cadmium (his 

 Traite, p. 36). Thiersch's Lead Chromate {Arch. mik. Anat., 1865, 

 p. 149). Hoyer's Lead Chromate {ibid., 1867, p. 136) ; or, for any of 

 these, see early editions. 



533.- Ranvier's Gelatin Mass for Impregnation {Traite, p. 123). 

 Concentrated solution of gelatin, 2, 3, or 4 parts ; 1 per cent, nitrate of 

 silver solution, 1 part. 



Neuville {Ann. Sci. Nat., xiii, 1901, p. 36) takes a solution of 10 grm. 

 of soaked gelatin in 100 e.e. of 1 per cent, solution of nitrate of silver. 



534. Friendethal's Hardening Mass {Centralb. Phys., xii, 1899, 

 p. 267). A 10 per cent, solution of gelatin, combined with a colouring 

 mass, and with 1 volume of 4 per cent, formol, serves for injecting 

 vessels and hardening the tissues at the same time. 



