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XXXVI. 0?^ the Mutual Relations of the Vital and Physical Forces 
By William B. Carpenter, M.D., F.R.S., F.G.S., 
Examiner in Physiology and Comparative Anatomy in the University of London. 
Received June 20, — Read June 20, 1850. 
I. Introductory Remarks. 
The degree to which the phenomena of Life are dependent upon Physical agencies, 
has been a subject of inquiry and speculation among scientific investigators of almost 
every school. That many of the actions taking place in the living body are con- 
formable to the laws of mechanics, has been hastily assumed as justifying the con- 
clusion that all its actions are mechanical ; and hence arose the iatro-mathematical 
doctrines, which obtained considerable currency among the physicians and physio- 
logists of the seventeenth century'!'. In like manner, the fact that many of the 
* The author thinks it due to himself to state, that the inquiry whose results are embodied in this paper 
has been occupying his attention for some years ; in proof of which he may cite the following passage from a 
review of Prof. Mattexjcci’s “ Lectures on the Physical Phenomena of Living Beings,” contributed by him to 
the “ British and Foreign Medico-Chirurgical Review ” for Jan. 1848 (p. 235): — “ There can be no doubt that 
the present tendency of scientific investigation is to show a much more intimate relation than has been com- 
monly supposed to exist between vital arid physical agencies ; and to prove that, whilst the former are of a 
nature altogether peculiar, they are yet dependent upon conditions supplied by the latter. And the more 
closely these phenomena are investigated, the more intimate and uniform does that dependence appear; so 
that we seem to have the general conclusion almost forced upon us, that the vital forces of various kinds bear 
the same relation to the several physical forces of the inorganic world, that they bear to each other ; the great 
and essential modification or transformation being eflPected by their passage, so to speak, through the germ of 
the organic structure, somewhat after the same fashion that heat becomes electricity when passed through cer- 
tain mixtures of metals.” Of the paper communicated by Dr. Fowler to the British Association at its last 
meeting (September 1849) under the title — “ If Vitality be a Force having Correlations with the Forces, Che- 
mical Affinities, Motion, Heat, Light, Electricity, Magnetism, Gravity, so ably shown by Professor Grove to be 
modifications of one and the same Force ? ” — he has no more knowledge than that which he has obtained from the 
short abstract of it in the Report of that meeting, published since the greater part of his own paper had been 
written ; and whilst it is evident from that abstract that Dr. Fowler has been pursuing the same line of inves- 
tigation with himself, and with somewhat of the same results, he has not thought this a sufficient reason for 
keeping back his own communication from the Royal Society. For he thinks it will appear, from the extract 
he has cited, that he may fairly claim priority in the enunciation of. the idea', and he ventures to believe that 
the systematic working out of that idea, which he has attempted in this paper, will give it a claim to the con- 
sideration of physicists and physiologists, such as it scarcely derives from the treatment which it has received 
from Dr. Fowler — so far, at least, as the author can judge from the abstract referred to. (See the Supplemen- 
tary Note, p. 757.) 
f “ The body,” says Dr. Bostock (History of Medicine, p. 165), “ was regarded simply as a machine com- 
posed of a certain system of tubes ; and calculations were made of their diameter, of the friction of the fluids in 
