INTRODUCTION 3 
from the relatively simple case of timber, which is 
felled, dried, cut up and distributed, to fats and volatile 
oils, glucosides and alkaloids, which require elaborate 
processes of chemical manufacture for their production 
and extraction. 
Sometimes the source is a wild plant available in 
quantity. Such are the timber trees of primeval forests, 
Para rubber as it grows in Brazil, esparto grass for 
paper making, and a host of others. Nevertheless, 
there remain a very great number of wild plants, grow- 
ing socially in immense stands and easy to get, for which 
no remunerative use has been found. For instance, 
the bracken fern, an almost cosmopolitan plant, is 
useless except for litter, whilst the Zostera of the sea 
shore, available in unlimited quantities, makes a stuffing 
for inferior mattresses, and has a limited use as packing 
material for venetian glass. On the whole, wild plants 
are exploited much less than might be expected. Their 
exploitation requires fertility in ideas and courage in 
their development; for the product to be a success 
must either displace some staple, or it must satisfy 
some taste or fulfil some requirement not yet created. 
In the one case the exploiter is up against a vested 
interest, in the other against inertia. On the whole, 
there is a great tendency to introduce and cultivate 
established plants rather than to improve and make 
valuable the indigenous plants of a territory. The 
empire affords many examples of this. 
Moreover, in the exploitation of wild plants there is 
always a liability to overcropping and destruction with- 
out replacement, so that in the absence of regulation 
the source gets more and more inaccessible. It then 
