254 CORROSION, DECALCTFICATION, AND BLEACHING. 



chromic solutions may be changed to yellow by means of oxy- 

 genated water (see Arch. f. mik. Anat., 1887, p. 47 and 

 Journ. Roy. Hie. floe., 1887, p. 1060). 



548. Eau de Labarraque. Eau de Javelle (see 528, 529). 

 These are bleaching agents. For the manner of preparing a 

 similar solution see Journ. de Microgr., 1887, p. 154, or Journ. 

 Roy. Hie. Soc., 1887, p. 518. It is, shortly, as follows : 8 

 parts of caustic soda are dissolved in 100 parts of distilled 

 water, and chlorine is passed through to saturation. During 

 the passage of the chlorine the solution must be surrounded 

 with a mixture of salt and ice, otherwise the temperature 

 rises, and chloride and chlorate of soda are produced. The 

 resulting solution contains 7*45 per cent, of hypochlorite of 

 soda. It is green; and the more effectual the cold, the 

 greener is the colour. The energy of the decolourising action 

 is proportional to the greenness of the solution. 



549. Chloroform helps to clear strongly pigmented chitin, 

 and combined with nitric acid will decolourise it entirely 

 (see below, in the chapter on Arthropods, Part II). 



550. GRENACHEK'S Mixture for Eyes of Arthropods and Other 

 Animals (Abh. nat. Ges. Halle-a.-S., xvi; Zeit.f. wiss. Mik., 

 1885, p. 244). 



Glycerin ...... 1 part 



80 per cent, alcohol . . . . 2 



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

 Pigments 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. You may, if you like, first stain 

 the objects with borax-car mine, and then put them into the 

 liquid the pigment being washed out more rapidly than the 

 carmine. But the progress of the decolouration must be care- 

 fully watched. 



