of locating Sugars in Plant Tis sties. 389 
sugar, so that as a little water is present in tissues at the commencement of 
heating, it is quite possible that the reagent is more sensitive to cane sugar 
in actual practice than the above experiments would suggest. Moreover, 
an acid cell-sap, &c., would assist in the hydrolysis of the cane sugar. 
Maltose, after being heated for an hour, forms a golden yellow syrup 
from which crystals may slowly form. In a mixture containing 1 per cent, 
of sugar only the syrup was produced, and this appeared in the form of 
a coarse emulsion; but with a 10 per cent, mixture, after a day or two, 
there resulted a small crop of fairly large, straight, linear-lanceolate, obtuse- 
ended crystals arranged either radially in spherical clusters or in various 
irregular groupings. The yield increased slowly over a number of days. 
Many of the clusters were almost opaque, and their crystalline nature could 
only with difficulty be made out. 
The presence of impurities in the form of various cell contents, 
particularly colloidal substances, probably influences the crystallization of 
the syrupy osazone, and may account for some irregularity in its behaviour 
in plant tissues. 
From observations on the process of crystallization of maltose phenyl- 
osazone in glycerine, it is concluded that the production of a golden yellow 
syrup inside starch-forming cells, or conducting cells of starch-forming 
organs, which have previously been treated with Senft’s reagent, very 
probably indicates the presence of maltose. 
It is suggested that a commonly observed granular appearance of this 
liquid may be due to one or more of the following causes: 
(a) Crystallization of syrupy maltose phenylosazone ; 
( b ) Partial hydrolysis of maltose originally present with production of 
dextrose and its osazone; this may occur during the heating in Senft’s 
reagent, or the maltose may have been undergoing enzyme hydrolysis at 
the time of applying the reagent; 
(c) Similar hydrolysis of cane sugar present with maltose, and con¬ 
sequent production of invert sugar yielding osazones ; 
(d) Presence of maltose, together with hexoses not produced by 
hydrolysis of disaccharides, i. e. ‘ up-grade ’ hexoses. 
Maltose appears to retard precipitation of osazone crystals of the 
hexoses ; this effect is more marked with dextrose than with levulose. 
The reagent itself gives no crystals after two or three hours’ heating, 
and if properly filtered in preparation only small traces of syrup are formed. 
If old, however, or much exposed to air, the reagent alone after heating for 
an hour or so may yield crystalline compounds and syrup after some months 
standing. This does not occur in properly closed preparations in which 
moderately fresh reagent has been used. The presence of water assists in 
the formation of these products. It is as well to renew the phenylhydrazine 
hydrochloride solution at least once every six months. 
