REVIEWS. 
345 
influence of others. At the same time, we cannot gainsay 
that many among them possess, independently of this gene- 
ral influence, particular properties, by virtue of which they 
exert their actions specially on certain organs, and seem to 
run about, as a certain author has it, making choice of, by a 
sort of elective faculty, the organ best suited to them out of 
all entering into the composition of the animal machine. In 
this way it is, for example, that the preparations of iodine, 
although they operate in modifying the entire animal economy, 
produce, notwithstanding, not less essential effects in the sys- 
tem, and these principally on glandular bodies. Likewise, 
thus it is that tartar emetic, although possessed of the pro- 
perty of irritating every tissue placed in contact with it, 
not the less retains the power of exciting its essential action 
of vomiting, in whatever ways it may, besides, affect the body. 
The vast number of analogous facts with which observa- 
tion has enriched the science of medicine, teach us that in 
those medicaments possessing general or common properties 
reside special or particular ones. 
Medicaments, as was observed before, not being very 
numerous, will admit of being ranged under two grand divi- 
sions, of which the first will comprise the debilitants , and the 
second the excitants . 
There are but few substances which do not enter in some 
respects into one or other of these grand divisions ; though 
some we encounter, having a mixed action, or one sui generis , 
are removed to a distance equally from the class of excitants 
and that of debilitants, though these are exceptions from which 
the best systems of classification are not entirely exempt. 
The particular properties, many times more numerous and 
varied than the general, will afford room likewise for a still 
greater number of divisions. 
***** 
Substances having particular properties, the same as those 
possessing but general ones, appear but little susceptible of 
bringing about salutary changes, but by virtue of the faculty 
they possess of modifying the primitive condition of organs. 
Nevertheless, some among them seem to exert this power 
