328 CHAPTER XXV. 



576. Eau de Labarraque. Eau de Javelle (see 555, 556). These 

 are bleaching agents. For the manner of preparing a similar solution see 

 previous 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) (POUCHEI'S 

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

 glycerin, to which has been added a little oxygenated water 

 (5 to 6 drops to a watch-glass of glycerin). SOLGKR 

 (Gentralbl. mecL Wiss., xxi, 1883, p. 177) takes a 3 per cent, 

 solution of peroxide. FURST (Morph. Arb., Schivalbe, 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 previous editions. 



579. Sulphurous Acid. Prof. G-ILSON writes me that he 

 finds alcoholic solution of sulphurous anhydride (S0 2 ) very 

 convenient for the rapid decoloration of bichromate objects. 

 A few drops suffice. MONCKEBERG and BETBE ( Arch. f. m%k. 

 Anat., liv, 1899, p. 135; Zeit. f. wins. Mik., xvi, 2, 1899, 

 p. 244) obtain the acid by adding to 10 c.c. of a 2 per cent, 

 solution of bisulphide of sodium 2 to 4 drops of concentrated 

 hydrochloric acid. Objects a.re put into the freshly pre- 

 pared solution for six to twelve hours. 



580. Permanganate of Potash. ALFIEEI (Monitore Zool. Hal, viii, 



1897, p. 57) bleaches celloidin 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. 



581. GBENACHEE'S Mixture for Eyes of Arthropods and other 

 Animals (AbJi. nat. Ges. Halle-a.-S., xvi ; Zeit. f. wiss. Mik., 1885, p. 244). 

 Glycerin . . . . .1 part. 



80 per cent, alcohol . . . .2 parts. 



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



Pigments [i. e. those in question] dissolve in this fluid, and so doing form 

 a stain which suffices in twelve to twenty-four hours for staining the nuclei 

 of the preparation. 



