174 



A TEXT-BOOK OF BOTANY. 



tion method, that they contained arbutin. The latter is a rather 

 widely distributed glucoside in this family and yields upon treat- 

 ment with solutions of emulsin or hydrochloric acid the sublimable 

 principle hydrochinon. The latter forms prisms and plates and 

 may be further examined with acetone solution, dilute solutions of 



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FIG. 101. Alkaloids of hydrastis obtained by microsublimation. The method fol- 

 lowed by Tunmaftn is to mix from o.oio to 0.050 Gm. of powdered hydrastis with a drop of 

 water upon a glass slide and heat to a temperature of 80 to 95 C. The sublimate consists 

 )f a number of radiating particles in which different types of crystals very soon separate (A). 

 The microsublimate may be further treated with alcohol and a solution of potassium iodide, 

 when crystals of hydrastine (B) and needle-shaped crystals of berberine (C) form. After 

 Tunmann in Gehe & Co.'s Handelsbericht, 1912. 



ferric chloride and ammonia water. Arbutin occurs in the 

 leaves of Arctostaphylos Uva-ursi, Vaccinium Myrtillus, Kahnia 

 angustif cilia, and Pyrola rotundifolia. 



Rosenthaler obtained definite crystals in the microsublimation 

 or pyro-analysis of the following drugs : cinchona, uva-ursi, f ran- 



