io6 
THE AMERICAN BOTANIST. 
local pharmacopeia, making substitutes of indigenous plants for 
those known at home. 
By careful botanical study, he not only learns to systematize 
and generalize—useful pursuits both, when infused with life— but 
also to detect adulterations and frauds, to hate quackery and 
pseudo-science, and to foster only what is experimentally proved 
to be useful, or by logical inference presumed to be so. Apart 
from immediate and tangible results, the incidental training in ob- 
servation, comparison, diagnosis, must inevitably redound to one's 
mental advantage. 
The study of medicine is almost coeval with the origin of the 
human race. With man came woe and the desire to relieve it. 
Says Cabanis : ''As man cannot exclude himself entirely from the 
constant agency of many external causes ; and as he carries with 
him several others wdiich are destined to- act at particular periods 
of life, or which may at any time exert their influence; we may 
with safety aflirm that the flrst trials of particular remedies bear 
almost as ancient a date as the existence of man himself. Among 
the most rude and uncultured tribes,as those of New Holland 
and New Zealand, of Lapland and Greenland, of North Ameri- 
ca and tne interior of Africa, we find traces of the practice of 
Imedicine and surgery." 
HOW INDIA RUBBER IS OBTAINED. 
The true 'Tara," India rubber (Hevia) is to be found growing 
naturally within the immense forest-covered area of the valley of 
the Amazon and in the tributary rivers, including the head 
streams of the Orinoco. I found it abundant high up on the Or- 
inoco, above the junction of the Guaviare (the latter stream by 
right indeed, should be styled the head stream of the Orinoco) . 
It is plentiful on the banks of the Cassiquiare-that curious bifur- 
cation by which the Orinoco gives a stream to the Rio Ne^^ro, and 
so converts Guayana into an immense island. I also found it 
growing in the interior betwixt the Tapajos and the Xingu. The 
rivers from which the largest supply is drawn now by traders are 
the I'urus and the Maderia. In its native forests it grows: dis- 
persed among the other forest trees, two or three trees rarely be- 
