638 SOME OF THE POSSIBILITIES OF ECONOMIC BOTANY. 
gossypium, or cotton, but experiments more or less systematic and 
thorough are being carried on with regard to the improvement of the 
varieties of the species. Plant hairs for the stuttiing of cushions and 
pillows need not be referred to in connection with this subject. 
Countless sorts of plants have been suggested as sources of good 
bast-fibers for spinning and for cordage, and many of these make capital 
substitutes for those already in the factories, but the questions of cheap- 
ness of production, and of subsequent preparation for use, have thus far 
militated against succesg. There may be much difference between the 
profits promised by a laboratory experiment and those resulting from 
the same process conducted on a commercial scale. The existence of 
such difference has been the rock on which many enterprises seeking to 
introduce new fibers have been wrecked. 
In dismissing this portion of our subject, it may be said that a proc- 
ess for separating fine fibers from undesirable structural elements, and 
from resin-like substances which accompany them, is a great desidera- 
tum. If this were supplhed many new species would assume great 
prominence at once. 
VI.—TANNING MATERIALS. 
What new tanning materials can be confidently sought for? In his 
Useful Native Plants of Australia, Mr. Maiden describes over thirty 
species of “ Wattles” or Acacias, and about half as many Euecalypts, 
which have been examined for the amount of tanning material contained 
in the bark. In all, eighty-seven Australian species have been under 
examination. Besides this, much has been done looking in the same 
direction, at the suggestion and under the direction of Baron von 
Mueller, of Victoria. This serves to indicate how great is the interest in 
this subject and how wide is the field in our own country for the intro- 
duction of new tanning plants. 
It seems highly probable however that artificial tanning substances 
will at no distant day replace the crude matters now employed. 
VII.—RESINS, ETC. 
Resins, oils, gums, and medicines from the vegetable kingdom would 
next engage our attention if they did not seem rather too technical for 
this occasion and to possess an interest on the whole somewhat too 
limited, but an allied substance may serve to represent this class of 
products and indicate the drift of present research. 
India Rubber.*—Under this term are included numerous substances 
which possess a physical and chemical resemblance to each other. An 
Indian Ficus, the early source of supply, soon became inadequate to 
furnish the quantity used in the arts even when the manipulation of 
rubber was, almost unknown. Later, supplies came from Hevea of 
*J, R, Jackson, Commercial Botany of the Nineteenth Century, 
a 
