TOBACCO, 473 
It is a remarkable law of the animal economy, 
that the power of use and habit is capable of 
reconciling the system to bear with impunity 
what in its unaccustomed state proves highly 
deleterious and even fatal. It isa fact that most 
substances in the Materia Medica lose their effect 
after the continuance of their use for a certain 
length of time, so that if we would realize their 
original operation, we must increase their dose in 
proportion as the body becomes accustomed 
and insensible to their stimulus. This is partic- 
ularly exemplified in the narcotics. Many of 
these substances, which at first are not only nau- 
seous and disgusting in their sensible qualities, 
but highly injurious in their influence upon 
health ; are so changed in their effect by habitual | 
use, as to become to those who employ them an 
innocent and indispensible comfort and a_ first 
rate luxury of life. : 
In its external and sensible ieaialiihi there 
is no plant which has less to recommend it than 
the common Tobaceo. Its taste in the green 
state is acrid, nauseous and repulsive, and a small 
quantity taken into the stomach excites violent 
vomiting, attended with other alarming symp- 
toms. Yet the first person who had courage and 
patience enough to persevere in its use, until hab- 
