APPENDIX. 265 



d. Schultze's Solution. Dissolve as much metallic 

 zinc in hydrochloric acid as will dissolve ; then add as 

 much iodine as will dissolve ; filter through glass wool. 

 This is the test for cellulose ; it turns normal cellulose 

 blue or violet, fungous cellulose yellowish brown. 



e. Schultze's Macerating Mixture. This consists of 

 nitric acid to which a few crystals of potassium chlorate 

 are added when used. This solution is used to separate 

 the fibers of woody tissues. The piece of plant should be 

 placed in a test tube, covered with nitric acid, and a little 

 potassium chlorate added. The tube should be heated to 

 the boiling point, and then its contents should be poured 

 into a large volume of water to stop the action and wash 

 out the acid. The plant tissues can then usually be easily 

 separated with dissecting needles. 



/. Caustic Potash. The usual strength should be 

 1 g. of the solid to 20 c.c. of water. This is used as 

 a macerating fluid, and also to cause the cellulose con- 

 stituents of plants to swell and become more plainly visi- 

 ble under the microscope. 



g. Millon's Reagent. Dissolve a small globule of 

 mercury in nitric acid and add an excess of the acid. 

 This solution is used to test for protein ; it turns protein- 

 aceous substances red. 



h. Osmic Acid. This expensive reagent may be pur- 

 chased in tubes containing 1 g. each. The tube should 

 be broken under the surface of the water in which 

 its contents are to be dissolved, as the fumes from the 

 acid are very disagreeable and poisonous. One .gram to 

 500 c.c. of water is a good strength for ordinary use. The 

 solution does not keep well. It is the test for oils and fats. 



i. Sulphuric Acid. The commercially pure acid should 

 be used either in full strength or diluted to various 

 degrees. This acid dissolves pure cellulose, but acts only 

 slightly on the older modified forms of cellulose. 



