752 
DR. CARPENTER ON THE MUTUAL RELATIONS OF 
dormant, by another which is expended in thus evoking it. Such an analogy should 
rather lead the physiologist to look for some extraneous source of the organizing 
force ; and to suspect that when organizable materials are applied to the extension of 
a living structure, and are caused to manifest vital forces, some agency external to the 
organism is the moving spring of the whole series of operations. And thus, according to 
the view here advocated, the vital force which causes the primordial cell of the germ 
first to multiply itself, and then to develope itself into a complex and extensive organ- 
ism, was not either originally locked up in that single cell, nor was it latent in the 
materials which are progressively assimilated by itself and its descendants ; but is 
directly and immediately supplied by the Heat which is constantly operating upon it, 
and which is transformed into vital force by its passage through the organized fabric 
that manifests it. The facts already cited, which show how completely dependent the 
process of germ-development, both in plants and animals, is upon the constant 
agency of heat, and how precisely its rate may be regulated by the measure of that 
force supplied to it, appear to the author to be so much better accounted for upon 
this view than upon either of the others, that he ventures to think that they de- 
monstrate it almost as fully as the nature of physiological evidence will admit. 
Having thus contrasted the doctrine for which he is contending, with those which 
are current among physiologists, the author thinks it well to point out that he no 
more regards heat as the “ vital principle,” or as itself identical with the vital 
force,” than it is identical with electricity or with chemical affinity. Nor does he in 
the least recognize the possibility, that any action of heat upon the inorganic ele- 
ments can of itself develope an organized structure of even the simplest kind. The 
pre-existence of a living organism, through which alone can heat be converted into 
vital force, is as necessary upon this theory, as it is upon any of those currently re- 
ceived amongst physiologists. And it is the speciality of the material substratum 
thus furnishing the medium or instrument of the metamorphosis, which in his opi- 
nion establishes, and must ever maintain, a well-marked boundary-line between the 
Physical and the Vital forces. Starting with the abstract notion of Force, as ema- 
nating at once from the Divine Will, we might say that this force, operating through 
inorganic matter, manifests itself in electricity, magnetism, light, heat, chemical affi- 
nity, and mechanical motion ; but that, when directed through organized structures, 
it effects the operations of growth, development, chemico-vital transformation, and 
the like ; and is further metamorphosed, through the instrumentality of the struc- 
tures thus generated, into nervous agency and muscular power. If we only knew of 
heat as it acts upon the organized creation, the peculiarities of its operation upon 
inorganic matters would seem as strange to the physiologist, as the effects here attri- 
buted to it may appear to those who are only accustomed to contemplate the physi- 
cal phenomena to which it gives rise. 
The variety of organic forms called forth by the agency of heat, which may be 
regarded as the products of its operation upon living germs, does not present any 
