LECTURES ON CHEMISTRY. 
771 
the water that may be near; and, knowing the cause, we have 
at once a clue given us to the remedy. 
I think that I have now stated enough to shew the advan- 
tages resulting from a knowledge of chemistry as applicable to 
the detection of the cause of disease, and also the remedies that 
should be had recourse to. We have likewise a proof, if any 
were wanting, of the kind of standing which the man of scien- 
tific attainments takes above him who is a mere empiric or char- 
latan, and whose treatment of disease rests upon a number of 
musty nostrums, which may chance to do good, but are quite as 
likely to do harm. 
There yet remains another division, in which an application of 
the principles of chemical science will be perceived to be fraught 
with the utmost importance. It is as they are made subservient 
to life. 
in the former part of this lecture I have referred to the fact, 
that animals decompose the air they breathe, removing the oxy- 
gen, and giving out carbonic acid gas. What is the more imme- 
diate result of this ? What the advantage to the animal frame 
alone considered ? It is that the vitiated venous blood, ren- 
dered so by the presence of carbonic acid, and hence unfit for 
the purposes of life, is, during its passage through the lungs, 
deprived of this noxious principle, it being thrown off during ex- 
piration, and, during inspiration, oxygen is absorbed in its place, 
which renders the blood arterial and fit to excite the various or- 
gans of the body into action, and at the same time perfects it in 
its constitution. 
The heat of the body is also in a great measure dependent on 
this change, namely, this condensation of oxygen, and conversion 
of it into carbonic acid ; although it must be allowed that the 
sanguiferous system is subjected to the control of that highest prin- 
ciple in the animal economy — the nervous. Of course, this too will 
again come under our notice, and in a more extended manner. 
The function of digestion, which is essential to the maintenance 
of the life of the animal, also receives elucidation by chemical in- 
quiry. This must, however, be accepted with some restriction, for 
the laws which govern life — to me at least — seem to control those 
of chemistry and mechanics ; both of which, however, are in 
operation in the living frame. 
Thus have I brought forward a few only of the many advan- 
tages which result from the study of the science of chemistry, and 
yet sufficient, I hope, to convince you of its importance. Its pur- 
suit will awaken a spirit of inquiry; a fondness of reasoning on 
effects, and of tracing these effects up to their causes ; while its 
possession will fill the mind with pleasurable feelings, and instil 
