Dr. Blank's Account , &c. 2% 
from all others. For want of fuch defcriptions, the know- 
ledge contained in the writings of the ancient naturalifts could 
be of ule only to their contemporaries and countrymen, who 
were already acquainted with the objects of it, and could 
afford no certain information to the ignorant in diftant coun- 
tries and future ages. Of all the ancient medicines, there 
is perhaps none but opium, of which the identity can be un- 
queftionably afcertained. Of mod: of them little more is faid 
than merely giving their names. But while nature is. conftant 
and invariable, language is local and fluctuating, fo that- feme 
of the mo ft important knowledge, though committed to wri- 
ting, refts upon little better foundation than if it were vague 
tradition. In confequence of this ambiguity, the fruits of the 
ingenuity and labour of one age have, in a great meafure, been 
loft to another; and ufeful inventions in various arts have be- 
come extiinft, for want of the means of afeertaining the ma- 
terials employed in them. Pofterity will therefore be greatly 
indebted to thofe induftrious naturalifts of the prefen t times 
w ho are carrying the defeription of nature to an unexampled 
height of improvement ; and our lateft defendants will be 
enabled, without difficulty, to avail themfelves of the accu- 
mulated experience of preceding ages. 
I have been led to thefe reflexions by an account, fen t me 
fome time ago by my brother in India, of the Spikenard, or 
Nardus Indica , a name familiar in the works of the ancient 
phyfieians, naturalifts, and poets ; but the identity of which 
has not hitherto been fatisfadtonly afeertained. Fie lays, in a 
letter dated Lucknow, December iy86, that, * 6 travelling 
with the Nabob Vifier, upon one of his hunting excurlions 
towards the northern mountains, I was furpnfed one day, 
u after croffing the river Rapty, about twenty miles from the 
“ foot: 
