NON-PROTOPLASMIC CELL CONTENTS 83 
applied to the walls of the cells. When these sections are treated 
with a 10 per cent. solution of alpha naphthol in alcohol and 2 or 3 
drops of strong H,SQOx,, the sphzro-crystals will dissolve with a 
violet color. Fehling’s solution is not reduced bv inulin. 
6. Grucosmes  (Glyco- 
sides)—These substances are 
very numerous in the plant 
kingdom. ‘They arise in the 
cell sap of plants containing 
them as products of constructive 
metabolism (anabolism) and Fic. 47,—Inulin, in the form of 
are thought by many to have sphzro-crystals from the tuber of Dahlia. 
the function of protecting plants A, precipitated from an aqueous solution; 
against the ravages of animals. 2 Precipitated within the cells by long 
standing in alcohol. (From Stevens, after 
Some are known to serve as Sachs.) 
reserve food. _All glucosides 
are characterized by the-property of being split up into glucose 
and other substances when acted upon by an enzyme, dilute acids 
or alkalies. 
EXAMPLES OF GLUCOSIDES 
HespEeripIN.—Hesperidin is a glucoside having the chemical 
formula of C2:,H2sO12. Like inulin it occurs in solution within 
the cell sap. It is found in abundance in the Rutacez family but 
occurs in many other plants. (See Fig. 85h.) 
If sections of alcoholic material containing this substance, such as Buchu leaves 
or unripe orange peel, are mounted in alcohol and examined, sphzro-crystals will 
be seen. If these are then treated with a drop of alpha naphthol solution and 2 
or 3 drops of strong H2SO,, they dissolve with a yellow color. The same coloration 
is evident when 5 per cent. solution of KOH is substituted for the alpha naphthol 
and H2SOx,. 
STROPHANTHIN.— This is a glucoside occurring in the cell sap 
of the endosperm of Strophanthus Kombe, S. hispidus and other 
species of Strophanthus. If sections of fresh Strophanthus seeds are 
mounted in a drop of water and then transferred to a drop of con- 
centrated H.SOx, the cells containing strophanthin will assume a 
bright green color. 
_Sazicin.—Salicin is a glucoside occurring in the cell sap of the 
bark and leaves of the Willows and Poplars. Sections of these 
