DUCALCL-^IOATION, DUS1UCIF1CAT10N, AND BLEACHING. 285 



GRYNFELTT and MESTREZAT ( C. R. Soc. BioL, Ixi, 1906, p. 87) add 

 2 c.c. of 20 per cent, solution of chloric acid (HC1O 3 ) to 15 c.c. of alcohol 

 and put sections (of retina) into it for several hours at 42 C. 



576. Eau de Labarraque. Eau de Javelle (see 552, 553). 

 These are bleaching agents. For the manner of preparing a similar 

 solution see early editions, or Journ. de Microgr., 1887, p. 154, or Journ. 

 Roy. Mic. Soc., 1887, p. 518. Of course, the method cannot be used for 

 bleaching soft parts which it is desired to preserve. 



577. Peroxide of Hydrogen (Oxygenated Water) (POUCHET'S 

 method, M. DUVAL, Precis, etc., p. 234). Macerate in 

 glycerin/ to which has been added a little oxygenated water 

 ( 35), 5 to 6 drops to a watch-glass of glycerin. SOLGEU 

 (Centralbl. med. Wiss., xxi, 1883, p. 177) takes a 3 per cent, 

 solution of peroxide. FURST (Morph. Arb. Schicalbe, vi, 



1896, p. 529) points out that after a time it macerates. 



The method serves both for removing pigments and for 

 bleaching osmic and chromic material. 



578. Peroxide of Sodium (CARAZZI, Zool. Anz., 444, 1894, p. 135). 

 See precious editions. 



579. Peroxide of Magnesium (MAYER, Grundzuge, p. 290). Use as 

 chlorine, 575. A slow but delicate method. 



580. Sulphurous Acid. Prof. GILSON writes me that he finds 

 alcoholic solution of sulphurous anhydride (S0 3 ) very con- 

 venient for the rapid decoloration of bichromate objects. A 

 few drops suffice. MONCKEBEEG and BETHE (Arch. mik. Auat., 

 liv, 1899, p. 135) obtain the acid by adding to 10 c.c. of a 

 2 per cent, solution of bisulphate of sodium 2 to 4 drops of 

 concentrated hydrochloric acid. Objects are put into the 

 freshly prepared solution for six to twelve hours. 



581. Permanganate of Potash. ALFIERI (Monitore Zool. Ital., viii, 



1897, p. 57) bleaches celloidiii sections of the choroid, etc., for eight to 

 twenty-four hours in a 1 : 2000 solution of permanganate of potash, then 

 washes them out for a few hours in a solution of oxalic acid of 1 : 300 

 strength, or weaker. 



582. GREN ACKER'S Mixture for Eyes of Arthropods and other 

 Animals (Abli. nat. Ges. Halle-a.-S,, xvi ; Zeit. wiss. Milt., 1885, p. 244). 



Glycerin ....... 1 part. 



80 per cent, alcohol 2 parts. 



Mix and add 2 to 3 per cent, of hydrochloric acid. 



