"As Sir H. Davy's experiments fully prove that electricity may be superadded to, and that it enters into, the composition of all those substances we call matter, I felt satisfied with the establishment of the philosophy of Mr. Hunter's views, nor thought it necessary to proceed further, but merely added: 'It is not meant to be affirmed that electricity is life.' I only mean to argue in favour of Mr. Hunter's theory, by showing that a subtile substance of a quickly and powerfully mobile nature seems to pervade everything, and appears to be the life of the world; and that therefore it is probable a similar substance pervades organized bodies, and is the life of these bodies. I am concerned, yet obliged, to detain you by this recapitulation, because my meaning has been either misunderstood or misrepresented[52]."
CHEMISTRY OF LIFE.
"He (Mr. Hunter) told us that life was a great chemist, and, even in a seemingly quiescent state, had the power of resisting the operations of external chemical agency, and thereby preventing the decomposition of those bodies in which it resided. Thus seeds may lie buried far beneath the surface of the earth for a great length of time without decaying, but being thrown up, they vegetate. Mr. Hunter showed us that this chemist, 'Life,' had the power of regulating the temperature of the substances in which it resides[53]."
INTERESTING; ALSO SIGNIFICANT IN REGARD TO WHAT ARE PROBABLY
THE REAL SOURCES OF ANIMAL HEAT, AND IN RELATION
TO THE LUNGS, WHICH WE HAVE CONTENDED ARE REFRIGERATING
AND NOT HEATING ORGANS.
"The progress of science since Mr. Hunter's time has wonderfully manifested that the beam, when dissected by a prism, is not only separable into seven calorific rays of different refrangibility, producing the iridescent spectrum, but also into calorific rays refracted in the greatest degree or intensity beyond the red colour, and into rays not calorific, refracted in like manner, to the opposite side of the spectrum beyond the violet colour; and that the calorific and uncalorific rays produce effects similar to those occasioned by the two kinds of electricity; and thus afforded additional reasons for believing that subtile, mobile substances do enter into the composition of all those bodies which the sun illumines, or its beams can penetrate.
"Late observations induce the belief that even light may be incorporated in a latent state with animal substances and afterwards elicited by a kind of spontaneous separation by vital actions, or by causes that seem to act mechanically on the substance in which it inheres. All the late discoveries in science seem to realize the speculations of ancient philosophers, and show that all the changes and motions which occur in surrounding bodies, as well as those in which we live, are the effect of subtile and invisible principles existing in them, or acting on them. Mr. Ellis, who, with such great industry and intelligence, has collated all the scattered evidences relative to the production of heat in living bodies, and added so much to the collected knowledge, seems to think that all the variations of temperature in them may be accounted for by known chemical processes.
"Here, however, I must observe, that Mr. Hunter's opinion of life having the power of regulating temperature was deduced, not only from his own experiments, related in the 'Philosophical Transactions,' but also from observing, that, in certain affections of the stomach, the heat of the body is subject to great vicissitudes, whilst respiration and circulation remain unaltered; and also that parts of the body are subject to similar variations, which appear inexplicable upon any other supposition than that of local nervous excitement, or torpor, or some similar affections of the vital powers of the part which undergoes such transitions[54]."