| 
ran) 
THE VOLATILE PAT OF PLANTS. 
At spring-time, in cold climates, the starch stored up 
over winter in the new wood of many trees, especially the 
maple, appears to be converted into the saccharose which 
is found so abundantly in the sap, and this sugar, carried 
upwards to the buds, nourishes the young leaves, and is 
there transformed into cellulose, and into starch again. 
The sugar-beet root, when healthy, yields a juice con- 
tiining 10 to 14 per cent of saccharose, and is destitute of 
starch. Schacht has observed that in a certain diseased 
state of the beet, its sugar is partially converted into starch, 
grains of this substance making their appearance. ( Wil- 
das Centralblatt, 1863, IL, p. 217.) 
The analysis of the cereal grains sometimes reveals the 
presence of dextrin, at others of sugar or gum. 
Thus Stepf found no dextrin, but both gum and sugar in maize-meal, 
(Jour. fiir Prakt. Chem., 76, p. 92;) while Fresenius, in a more recent 
analysis, (Vs. St., 1, p. 180,) obtained dextrin, but neither sugar or gum. 
The sample of maize examined by Stepf contained 3.05 p. c. gum and 
3.71 p. ec. sugar; that analyzed by Fresenius yielded 2.33 p. ¢. dextrin. 
Gum Tragacanth is a result of the transformation of 
cellulose, as Mohl has shown by its microscopic study. 
6. In the animal, the substances we have been describ- 
ing also suffer transformation when employed as food, 
During the process of digestion, cellulose, so far as it is 
acted upon, starch, dextrin, and probably the gums, are 
all converted into glucose. 
e. Many of these changes may also be produced apart 
from physiological igency, by the action of heat, acids, and 
ferments, operating singly or jointly. 
Cellulose and starch are converted by boiling with s 
dilute acid, into dextrin and finally into glucose. If pape: 
or cotton be placed in contact with strong chlorhydric 
acid, (spirit of salt,) it is gradually converted into the 
same sugar. Cellulose aid starch acted upon for some 
time by strong nitric acid, (aqua-fortis,) give compounds 
from which dextrin may be separated. Nitrocellulose, 
(gun cotton,) sometimes yields gum by its spontaneous 
