140 JOURNAL OF THE ROYAL HORTICULTURAL SOCIETY. 
equal to the demand, by making them into extract or other prepara- 
tions that will keep. 
If medicinal plants are grown on an ordinary farm where labour 
and animal manure are always available, the difficulties in the case 
of Belladonna and Henbane are, that unless the farmer has suitable 
drying apparatus he must sell the fresh plant, and if he is far from a 
large town the expense of cartage and rail considerably reduce his 
profits, and he is at the mercy of the buyer, who knows that the green 
herb must be sold within about a fortnight, or the plants will have 
passed their best condition. But if he has a good drying-house the 
farmer is able to keep the dried plants over the winter, and is thus 
able to secure some profit. 
As the wild plants are collected from estates by men who sell them 
without knowing their market value, and are therefore at the mercy 
of the buyer, they are sometimes bought up by growers who can dry 
them. The farmer who has no drying-house finds it better to grow 
potatos than medicinal plants. It will therefore be readily under- 
stood that the growers who have manufactories, and the growers who 
have drying-houses but no manufactories, are few in number, and 
when an unusual demand arises the prices both of the wild and the 
cultivated plants increase, and it is then that the Continental supplies 
are employed to lower the price of the home production. 
Collection of Medicinal Plants and Herbs. 
As a general rule, the direction given in the Pharmacopoeia for the 
collection of leaves is at the period when the flowers are beginning 
to open, because it is supposed that the active principles of the plant 
are then most abundant in the leaves, before migrating to the flowers, 
the active principle serving apparently as a protection against insects, 
and thus moving on from root to stem, leaf, flower, and seed, as each 
organ is successively developed. 
Roots are most active when the new root is fully formed, before 
the plant is developed, as in Aconite ; or in the case of some perennials 
like Dandelion, in the spring, before the flowers are developed. To 
some extent the collection of roots is ruled by other circumstances, 
such as the convenience of the farmer, as they are more easily and 
conveniently collected when the land is ploughed, or when the crops 
which permit it, such as turnips, are weeded. It is then comparatively 
easy for the weeders to put on one side in definite heaps such wild 
herbs as Fumitory, Parsley Piert, and Cudweed, which are common in 
cultivated fields. In collecting tall herbs, it is necessary to cut their 
stems off above where the lower leaves have turned yellow or brown, 
so that when dried they may present a bright, not faded, green colour. 
The collection should take place so far as possible on dry or sunny 
days. Easterly winds are particularly favourable for this purpose, 
as the dry air causes rapid withering, and facilitates the process of 
drying. Herbs should never be collected in wet weather. 
