118

HIS ESSAY ON THE SKIN, &c.

CHAPTER VIII.

HIS ESSAY ON THE SKIN AND LUNGS.

It is madness and a contradiction to expect that things which were never yet performed should be effected, except by means hitherto untried."-BACON, NOV. ORG. АРН. 6.

THIS simple and instructive aphorism, when we consider the object of the distinguished author in the immortal work whence it is taken, is highly suggestive to those who are aware of the present state of medicine and surgery, and who desire to see them become a definite science. Nor does it appear inappropriate to the consideration of Abernethy's experimental in

ADVANCE OF CHEMISTRY.

119

.quiries into the functions of the skin and lungs. An extended investigation of which this paper contains an excellent type, and is in part a practical application, would be a great step towards the creation of a real science, and would certainly fall within the "means untried" of Lord Bacon.

Although the latter part of the last century, and the first half of the present, have been very remarkable for the number of distinguished men who have flourished during that period, in almost every branch of knowledge, yet neither the bar nor the senate, neither literature nor any of the sciences can boast of greater men, nor lay claim to more positive improvement than Chemistry.

If we only consider that interval between the discovery of oxygen by Priestly, in 1774, and the conclusion of Sir Humphrey Davy's labours, Chemistry almost seems like a new science; and it continues to advance with such rapidity, and is daily opening out so many new questions, that the most accomplished chemist of one year is never sure how much he may have to

learn the next, nor, unless he reasons with great. caution, how much he may have to unlearn.

To a physiologist who requires assistance from all branches of science, Chemistry must always be an interesting study. When we lay aside all speculations as to what is the abstract nature of Life, and study that which is the proper object of philosophy-that to which it seems the faculties of man are limited—namely, the laws in obedience to which the phenomena in nature occur; and apply the knowledge thus obtained to the occurrences which take place in the human body; we soon discover that, whatever the abstraction "Life" may be, we live proximately, in virtue of certain changes in various forms of matter; as food, air, the various constituents of our bodies, &c.-and that these consist of multiplied separations and rearrangements of their respective elements, which it is the special province of Chemistry to examine.

If we investigate the changes of the living or the structure of the dead with these objects, we shall be in no danger of abusing Chemistry to purposes to which it is inapplicable. When,

however, we proceed a step further, and seek to give a chemical expression to various uses and relations of different parts of the body, the greatest caution is required.

In the first place, in a machinery which is a practical application of a great many sciences, it is to the last degree improbable that they can be expressed by any one.

Again, to estimate the true meaning-the physiological interpretation of many changes which might be in their proximate sense chemical-a greater familiarity with the phenomena of disease is necessary than usually falls within the inquiries of the most scientific chemist.

To a person acquainted only with the ordinary phenomena of health, Chemistry is for ever suggesting tempting analogies, which are constantly tending to mislead him to conclusions on insufficient data; and to examine and rest too much on the chemical facts deducible from one or other function, without sufficiently attending to the physiological relations of that function with all others.

In fact, for want of due caution, or it may be

of a sufficient range of information, the assistance which Chemistry has hitherto rendered to Physiology has been attended with so many assumptions, that it is extremely difficult to say on which side the balance lies; of advantage or error. We are aware that at this moment there is a contrary feeling-a kind of furore for chemical solution of physiological phenomena. We believe the caution we venture on suggesting was never more necessary.

The discovery of oxygen gas by Priestley, not only gave a great impetus to chemical inquiries, but affected Physiology in a very remarkable manner; when it was found that the more obvious phenomena of all cases of ordinary burning, lamps, candles, and fires of every kind, consisted of the chemical union of charcoal and oxygen (carbonic acid), and again, when it was discovered that animals in breathing somehow or other produced a similar change, one may conceive how ready every one was to cry: "I "have found it! The heat of animals is "nothing more than combustion! We inhale

oxygen; we breathe out carbonic acid; the