OXYGENATED WATER. 253 



pipette, and mixed-in by shaking the vessel as soon as the 

 green colour of the evolving chlorine has begun to show itself. 

 Warm if necessary ; but most objects, even large ones, may be 

 bleached in half a day without the employment of heat. The 

 tissues do not suffer. 



Instead of hydrochloric acid, nitric acid may be used ; in 

 which case the bleaching agent is the freed oxygen, instead 

 of chlorine. 



The first method may be used for the purpose of removing 

 pigment from the eyes of insects. 



543. MAESH'S Chlorine Method (Section Cutting, p. 89). 

 Marsh generates chlorine in a small bottle by treating crystals 

 of chlorate of potash with strong HC1, and leads the gas (by 

 means of a piece of glass tubing bent twice at right angles) 

 to the bottom of a bottle containing the sections in water. 

 (See a fig. of the apparatus in Journ. Roy. Mic. Soc., iii, 1880, 

 p. 854.) 



544. Chlorine Solution (SARGENT'S method). Hydrochloric 

 acid, 10 drops ; chlorate of potash, | dr. ; water 1 ounce. 

 Soak for a day or two. Wash well. 



This method is intended for "bleaching insects;" it will 

 be seen that it is only applicable to the preparation of hard 

 parts, as soft tissues would be destroyed by the solution. 



545. Kreasote (POUCHET'S method, Journ. de I'Anat., 1876, 

 p. 8, et seq.). I gather from the paper here quoted that 

 most of the granular animal pigments are soluble iiikreasote. 

 Other solvents are mentioned in this paper (" On the Change 

 of Colouration through Nervous Influence"), but this appears 

 to be the only one capable of general histological application. 



546. Nitric Acid. Nitric acid has a similar action. 



547. Oxygenated Water (POUCHET'S method, M. DUVAL, Precis', 

 8fc.) ]). 234). Macerate in glycerin to which has been added 

 a little oxygenated water (5 to 6 drops to a watch-glass 

 of glycerin). (Oxygenated water may be procured from per- 

 fumers or hair-dressers, by whom it is sold as a hair dye 

 under the name of " Aureoline," "Golden hair-wash," or the 

 like.) 



The brownish-green colour communicated to tissues by 



