ALCOHOLS. 27 



solubility in a warm solution of asparagin. The 

 same treatment may, perhaps, be used with effect 

 ia testing for other substances ; it has already 

 been found satisfactory for tyrosin. 



Alcohol is also employed as a solvent for a 

 part of the reagents used in micro-chemical tests ; 

 e.g. anilin dyes, corrosive sublimate, phloroglucin, 

 iodine, etc., as well as in the capacity of an anhy- 

 drating medium for preparations that are to be 

 mounted in volatile oils or Canada balsam. 



GLYCERINE. 



This fluid, 1 especially useful as a preservative 

 for permanent preparations, for which use I pre- 

 fer the nearly anhydrous form known as glyce- 

 rinum Wilsoni, is also employed for many other 

 purposes. According to circumstances it is diluted 

 with alcohol or water, or with both. Preparatory 

 to final mounting it is often well to place prepara- 

 tions temporarily in a mixture of equal volumes of 

 glycerine, distilled water, and absolute alcohol. 



It is used like alcohol as an anhydrating medium 

 in the study of protoplasm. It can be employed 

 very successfully as a clearing medium in many 

 cases ; e. g. in studying the histology of the fibro- 

 vascular bundles, and as a preservative or final 



1 Kraus: Bot. Zeitung, 1877, p. 329. Sachs: Bot. Zeitung, 1864, Nos. 

 12,13. Nageli: Das Mikroskop, 1877, p. 475. Hegelmaier: Entwick- 

 elung dicotyledoner Keime, p. n. 



