108 PLANT ANATOMY. 
For us the most remarkable and important constituent of the 
cell-contents is the starch (amylum '). 
The latter occurs abundantly, in the form of characteristic 
granules, in seeds and other receptacles of reserve substances 
(rhizomes, tubers). The seeds which are provided with starch 
(reserve-starch) are, however, very much less numerous than 
those which contain none. It appears also in the conducting 
tissues (transitory starch), and in the interior of the chlorophyll 
granules (assimilation-starch, autochthonous starch), but then 
mostly in very small granules. For our purpose, the starch 
granules of the reserve-receptacles are especially important. 
Between the starch and other constituents of the cells there 
exist manifold, but as yet only slightly explained relations. 
Thus in the case of Radix Belladonne, Budde’ has found cer- 
tain relations to exist between the amount of starch contained 
in the root and the amount of alkaloid. ‘The amount of atro- 
pine is most considerable in roots which are very rich in stareh, 
and least in those which are free from starch (compare also 
page 13). 
Starch is organized and appears in the form of more or less 
distinctly stratified granules? (Figs, 35, 36, 37, 39, 42, 43, 44, 
45, 46). 
Some drugs are exposed, in their fresh condition, to a higher 
temperature in order to dry them more quickly. If these parts 
of plants are juicy, the amylum thereby suffers that change 
which is known as the formation of paste. The granules swell 
to a high degree and flow together, to form structureless masses 
or balls of paste. Thus in the case of Curcuma,* Jalap, Salep, 
some varieties of Sarsapariila, and the East Indian Aconite 
tubers. Sago is nothing more than swollen and dried starch. 
The layers (which are especially handsome in the granules 
from the potato and leguminous seeds) are arranged around a 
'From a (a privative), and “vAy mill—flour prepared without a mill. 
* Archiv der Pharm., 220 (1882), 414. 
*Nageli, ‘Die Starkekérner, Pflanzenphysiologische Untersuchun- 
gen,” 1858. The most comprehensive work relating to starch, 
* Berg, ‘‘Anatomischer Atlas,” Taf. xix., Fig. 48, 
