302 THE ANIMAL AS A PRIME MOVER. 



work of one atmosphere, 15 pounds per square inch of section of fiber, 

 rising to somewhat higher figures; but all are very moderate intensi- 

 ties as compared with those adopted in machinery and in proportion to 

 weights developing them. None can therefore find in peculiar tenaci- 

 ties or intensities of action of working parts a means of attaining 

 remarkable power, even in the case of the bird, which was formerly 

 supposed to enormously excel all other creatures in its concentration 

 of power in mass and muscle. We seem thus reduced to the study of 

 the methods of transformation of energy of the foods. The fact that 

 venous blood is warmer than arterial, though very slightly, is another 

 evidence that the transformations of matter, as well as of energy, in 

 these processes occur in the muscular system; and the path into which 

 investigation must be turned would seem to be fairly well located. 



Dr. Carpenter was, perhaps, the first to elaborate fully and clearly 

 the idea that the germ of the organism is not the concentrated essence 

 and energy of the organism and all its progeny, but that it is rather 

 constituted as " a directive agency, thus rather representing the con- 

 trol exercised by the superintendent builder, who is charged with the 

 working out of the design of the architect, than the bodily force of 

 the workmen who labor under his guidance in the construction of the 

 fabric. 7 ' The actual constructive force, he thinks — as we now can see, 

 very possibly, wrongly — is heat. 1 



It may now be taken as certain that, as Dr. Carpenter asserted in 

 1850, ''in some way or other fresh organizing force is constantly being 

 supplied from without" during the whole period of activity of the vital 

 machine, which continues by inheritance to transmit the power of 

 absorption and transformation and of direction of this absorbed energy, 

 for all its various purposes, throughout the life of the whole line of its 

 posterity and that of the race. 



Liebig, Carpenter, Grove, and others have long ago prepared the way 

 for the acceptance of the proposition that the organs of the animal 

 which elaborate its powers constitute an apparatus fitted to simply 

 divert the energy received as latent in the food and awakened by the 

 chemical processes constituting digestion, assimilation, and nutrition, 

 and to direct it into its new channels in the form of heat, mechanical 

 energy, and vital power. Sir Benjamin Brodie found that the act of 

 respiration simply did not sustain the temperature of the body, and 

 that the action of the spinal column was essential to the normal devel- 

 opment of heat. Helmholtz found the chemical changes greater in 

 muscle in use than when at rest, and a larger proportion of waste, due to 



'"Thus in the case of the successive viviparous broods of the Aphides a germ 

 force capable of organizing a mass of living structures which would amount (it has 

 been calculated) in the tenth brood to the bulk of 500,000,000 of stout men most 

 have been shut up in a single individual weighing perhaps the one one-thousandth 

 of a grain, from which the first brood was evolved," if the theory was true; and 

 "the bodies of all men who have lived from the time of Adam to the present day 

 must have been concentrated in the body of their common ancestor." 



