JO SI AH WILLARD GIBBS 197 



pation of available energy, or the Gibbs-Helmholtz form of decrease 

 of free energy, is assumed by recent physiologists to be characteristic 

 of all spontaneous or metabolic processes, but both Helmholtz 143 and 

 Kelvin 144 have doubted whether it is either necessary or sufficient for 

 their production, while Maxwell 145 and Boltzmann 146 have asserted, 

 what Gibbs's statistical researches seem to prove, that it is sometimes 

 possible for entropy to decrease, that is for small isolated temporary 

 violations of the second law to occur in any real body. Has animal 

 or vegetable protoplasm ever the power ascribed to Maxwell's demon of 

 reversing the thermodynamic order of nature, and directing physico- 

 chemical forces? Such a demon, according to Lord Kelvin, might, 

 through his superior intelligence or motor activity, render one half of 

 a bar of metal glowing hot, while the other half remained icy cold. 

 We have something analogous to this in certain diseases, as gangrene, 

 aphasia, various forms of paralysis, the curious vasomotor and trophic 

 disorders of the nervous system. Are these phenomena then of a 

 thermodynamic nature? The animal body, Lord Kelvin thought, does 

 not act like a thermodynamic engine, but "in a manner more nearly 

 analogous to that of an electric motor working in virtue of energy 

 supplied to it by a voltaic battery." Here, as Gibbs has shown in his 

 theory of the chemical cells, the electromotive force would be identical 

 with the free energy upon which the surface energies of the body must 

 ultimately depend. Beyond these speculations Ave know nothing. 

 Gibbs himself avowed his express disinclination to " explain the mys- 

 teries of nature," while Lord Kelvin, although affirming that physicists 

 are bound " by the everlasting law of honor," to explain everything 

 material upon physical principles, mystified friends and opponents 

 alike by falling back upon a " vital principle " with " creative power " 

 behind it as the causa causans of biological happenings. But the busi- 

 ness of physics is with the material facts of the universe, and the invo- 

 cation of creative power explains nothing and is subversive of deter- 

 minism, or the relation of cause and effect in science. It may be that 

 " man was born too late to ascertain final causes " : he can only inter- 

 pret the physical facts of his experience as he finds them and with the 

 means at his disposal. An interesting attempt to explain the relation 

 of life and mind to matter is found in the energetische Weltanschauung 



1,3 Helmholtz, J. f. Math., v. 100, 137. Auerback, " Kanon der Physik.," 

 414. 



144 Kelvin, "Pop. Lect.," II., 199, 403, 464. See, also, the discussion in 

 Science, 1903, N. S., XVIIL, 138-146. 



145 Maxwell, Mature, 1877-8, XVII., 280. 



146 Der grosse Meister, dem auch diese Zeilen huldigen mochten, hat einst 

 den Gedanken ausgesprochen, dass es in der Welt vielleicht Stellen giebt, wo die 

 Entropie nicht wachst, sondern zunimmt," O. Chwolson. Boltzmann, 

 " Festschr.," 1904, 33. 



