COLLECTION AND PREPARATION. 13 
lows later on (p. 139), relating to the liquid contents of the 
plant cell, shows how great are the changes produced in the 
plant, simply through the process of drying. It is evident that 
these changes bave hitherto not been, by far, sufficiently consid- 
ered.’ They may often be surmised through changes in odor, 
as, for instance, in the case of coriander, the underground por- 
tions of Orchis (salep), Iris (orris root), Veratrum and Aconi- 
tum. Occasionally the drugs assume, upon drying, other col- 
ors. 
It is of special importance to determine accurately the proper 
time of collection of each plant, or of its officinal parts; for 
during the life of a plant it does not at all times contain the 
active principles in equal amount—indeed, in many plants, cer- 
tain constituents are, at some periods, entirely wanting. The 
time of collection is to be so chosen that the maximum amount 
of the desired substances is obtained. Quite independent, how- 
ever, of the impossibility of insuring this by watching the 
collectors, it must also be admitted that our scientific knowledge 
of these conditions is still altogether too fragmentary. In 
the case of Folia Digitalis, Folia Hyoscyami, Fructus Conti, 
Tuber Colchici, Rhizoma Filicis, and some few other crude 
vegetable substances, we are, however, in this respect well 
informed. 
Digitalis leaves are weaker in active constituents before the 
period of flowering than afterward, consequently the leaves of 
the first year are to be entirely rejected. In the case of Hyos- 
cyamus, the leaves of the second year’s growth are likewise 
preferred, at least in England. Schroff, in 1870, showed that 
Fructus Conii contains the largest amount of coniine immedi- 
ately before the period of ripening. To the same investigator 
we are indebted for the proof that Zuber Colchici is only active 
at the flowering period of the plant. Rhizoma Filicis, according 
to all experience, should only be collected in late summer. The | 
absolute age of the respective parts also comes often into con- 
sideration. Thus Radix Belladonne of the second or third year 
1 Experiments worthy of notice relating to this subject have 
already been made by Schoonbrodt. See Jahresbericht der Pharm., 1869, 
