384 Maugham.—Observations on the Osazone Method 
appearance recalled some stages observed in the formation of osazone 
crystals in preparations in which maltose had been heated with the reagent. 
On the whole it seemed fair to conclude that the osazone, which as the 
result of being heated had melted and had then been dispersed throughout 
the glycerine as an emulsion and partly as a solution, on cooling had 
gradually become aggregated into microscopically visible droplets which 
were in some cases very slowly undergoing re-crystallization from the 
syrupy condition. 
Although after six months from the time of mounting some of these 
spheres appeared distinctly more crystalline, the majority were still almost 
transparent and structureless. 
In addition to these observations, others were made on preparations 
which contained drops of the 1 per cent, and 5 per cent, mixtures described 
above, and which had been heated at 98° C. or so for \ hour, 1 hour, 1 ■§ hours, 
and o, hours respectively after having been set up. 
The early stages of the processes just dealt with were somewhat 
accelerated by the heating. About four months later it was found that, 
while the 1 per cent, mixtures which had been heated for 1 hour and 
1^ hours respectively showed only drops of yellowish-brown syrup, there 
also appeared in the other two 1 per cent, preparations a great number of 
much larger, pale yellow, spherical, semi-crystalline or granular masses. 
(Cf. PL XVII, Fig. 10.) 
These evidently consisted of osazone partially re-crystallized, and so 
afforded an example of a later stage in the process than could be seen in 
any of the unheated slides. After six months from the beginning of the 
experiment the osazone in all of these slides was found to have partially 
re-crystallized. 
It is clear, therefore, that even in 1 per cent, concentration the viscous 
syrup may under suitable conditions slowly crystallize. 
Crystallization is, however, uncertain and the osazone may remain 
either in solution or as a fine emulsion, or it may separate out as micro¬ 
scopically visible drops of syrup which apparently do not crystallize. 
Doubtless in this case, as with other organic compounds, the presence of 
impurities hinders crystallization of the syrup. It is known that in aqueous 
solutions the form of the crystals of maltose phenylosazone is greatly 
affected by small traces of impurities. 1 In the plant cell many substances 
are present and must constitute impurities; among these are colloids, the 
influence of which on crystallization may be very marked. 
Accordingly some lack of uniformity of the osazone of maltose is to be 
expected when it is formed inside vegetable cells, and especially inside 
sieve-tubes where proteins may abound. 
It cannot, of course be taken for granted that results yielded by extra- 
1 Armstrong, 1 . c., p. 60. 
