238 Sydney Mangham. 
The effect of glycerine on the re-crystallisation of osazones 
prepared from the various sugars used was also studied, the 
osazones being dissolved in the glycerine by heating. It was found 
that while some irregularities occurred, yet . . . crystallisation 
seems to be retarded by the viscosity of the glycerine. Naturally in 
a viscous medium the rate of diffusion of particles to form crystals is 
slower than in a medium such as water.” 1 
In the section entitled “ Reaction with Mixtures of Sugars,” 
attention was directed to the work of Scherman and Williams 
who, using various concentrations of sugars, found that levulose, 
in aqueous solution, precipitated its phenyl osazone in about one- 
third of the time required by the same concentration of dextrose. 3 
The point of all this is that ^-glucose and ^-fructose with 
phenylhydrazine yield osazones of the same chemical composition* 
but that this osazone is formed in the one case from an aldose and 
in the other from a ketose; the results of the experiments of 
Senft, Sherman and Williams, and myself indicate that the forma¬ 
tion of the osazone occurs more rapidly from cf-fructose than from 
<7-glucose in aqueous solutions, while in strong glycerine the 
viscosity of the medium retards the precipitation in both cases, 
and to some extent also affects the configuration of the resulting 
crystal clusters of the osazone, as shown by various figures and 
photographs in the papers under consideration. It is then a ques¬ 
tion of the influence of viscosity upon molecular rearrangements, 
diffusion and crystal formation. 
With regard to the use of Senft’s reagent for identifying 
maltose, difficulties undoubtedly exist, but here again they are due 
mainly to the influence of the glycerine ; this greatly retards, or 
may completely prevent the production of crystals from the familiar 
syrupy condition of the osazone. 
This effect of glycerine was studied both by producing the 
osazone from maltose in the presence of excess of strong glycerine, 
and by observing the re-crystallisation of the osazone from 
glycerine in which it had been heated.* 
As the result of the experiments performed the following 
opinions were expressed: 
“ Considerable caution must therefore be exercised in attempt¬ 
ing to locate maltose in starch-forming plants by means of Senft’s 
reagent. The formation of drops of syrupy liquid within cells, 
especially if in any quantity, and if in tissues examined after starch 
dissolution is known to have occurred, in all probability denotes 
1 l.c., p. 381. 2 l.c., 385-6. * l.c., pp. 378 and 381, 
