38 SECTIONAL ADDRESSES 
methods. It may well be that in the formation of cellulose in the plant 
a limited chain length of the chemical molecule is imposed by thermo- 
CH OMe 
Tetramethyl glucose. Trimethyl glucose + methyl] alcohol. 
Methylated Cellulose (+ = 200). 
dynamic considerations. We shall see, however, in the case of starch 
that molecular aggregation of the chemical molecule occurs freely in vitro, 
and is promoted by a choice of chemical reagents. Similarly, it has been 
found possible to effect the reverse change of disaggregation in the case of 
starch. Doubtless many of the common reactions to which cellulose is 
subjected in the laboratory and in industry are unconsciously directed to 
a disaggregation of the physical unit in order to promote more facile 
chemical change in the preparation of derivatives. ‘There is no doubt, 
as shown by our recent experiments, that progressive chemical break- 
down occurs the more drastic are the reagents used. Hydrocellulose 
has been found by the method of chemical assay to correspond to a chain 
length of rather less than half that of cellulose and is evidently degraded 
cellulose. Again, the use of oxidising agents promoting the formation 
of oxycellulose is accompanied by a more profound breakdown with the 
formation of portions of very short modified chains, and also invariably 
a residual portion for the most part consisting of a chain of 60-80 glucose 
units. Both hydrocellulose and oxycellulose are frequently formed in 
processes to which cotton is subjected. ‘These products may also accom- 
pany the use of chemical reagents which are empirically employed for the 
preliminary disaggregation of cellulose in the manufacture of the newer 
textiles. But these shortened cellulose chains represent the more soluble 
portions and may be removed by solution. 
An insight into the difficult problem of starch is slowly being gained. 
We have shown that the mode of linking of a large portion of the starch com- 
plex is represented by continuous units of «-glucopyranose linked through 
the positions 1 and 4. Here side by side there are given in perspective 
formule parts of the continuing chains of starch and of cellulose. It is well 
known that the starches contain combined phosphorus and silica, but the 
