Carbon Assimilation. 225 
(ii.) The pentosans form a larger and larger proportion of the 
matter insoluble in alcohol as the season advances. 
(iii.) Of the total sugar, the hexoses form a progressively 
increasing proportion as the season advances. This point has 
already been brought forward very clearly by Parkin in the case of 
the snowdrop (see Table XXXIV). 
