CHAPTER XXL 237 



Soc., 1889, p. 463 ; THIERSCH'S, Arch. mik. Anat., i, 1865, p. 148 ; FOL'S, 

 Zeit. iviss. Zool., xxxviii, 1883, p. 494 ; and previous editions. 



Other Colours. 



488. HOYER'S Silver Nitrate Yellow Gelatin Mass (Biol. CentralbL, 

 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 489. 



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

 vessels. 



489. 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. wiss. Zool., xxxviii, 1883, p. 494). MILLER'S Purple (see 

 Amer. Mon. Mic. Journ., 1888, p. 50 ; Journ. Boy. 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. 



490. 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 grms. 

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



491. FRIEDENTHAL'S Hardening Mass (Centralb. Phys., xiii, 1899, 

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

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

 vessels and hardening the tissues at the same time. 



