TEGUMENTARY ORGANS 441 



a negatively impregnated cornea with weak salt solution or weak 

 solution of hydrochloric acid (His). 



But the best positive images are those furnished by gold chloride. 

 Ranvier prefers his lemon-juice method. It is important that 

 the cornea should not remain too long in the gold solution, or the 

 nerves alone will be well impregnated. 



Zawarsin {Arch. niik. Anat., Ixxiv., 1909, p. 116) removes the 

 membrane of Desccmet for study in the following manner. A 

 cornea, fixed in sublimate, is dissected out and put for some 

 hours into a mixture of alcohol and ether. The collodion of 4 

 per cent, is poured on to the inner surface, and after some time 

 a layer of collodion with the membrane attached can be peeled 

 off, and the collodion removed from the tissue by a mixture of 

 alcohol and ether. 



See also Rollett, in Strieker's Handb., pp. 1102, 1115, or 

 previous editions ; Tartuferi, Anat. Anz., v, 1890, p. 524, or 

 previous editions ; Ciaccio, Arch. ital. Biol., iii, p. 75 ; and 

 Renault, C. R. Acad. Sc, 1890, p. 137. 



940. Crystalline. Gerhardt {Zeit. wiss. Mik., xiii, 1896, 

 p. 306) hardens the lens for one or two days in 4 to 10 per cent, 

 formalin ; it is then easily dissociated with needles into its 

 fibres. 



Rabl {Zeit. wiss. ZooL, Ixv, 1'898, p. 272) fixes the enucleated 

 eye for half an hour in his platinum chloride or picro-sublimate, 

 §§ 80 and 75, divides it at the equator, and puts the anterior 

 half back for twenty-four hours into the fixative. 



For Maceration you may use sulphuric acid, § 575. 



See also Robinski, Zur Kenntnis d. Augenlinse, Berlin, 1883. 



