I] OF DYNAMICAL MORPHOLOGY 9 



of the body, as of all that is of the earth earthy, physical science 

 is, in my humble opinion, our only teacher and guide*. 



Often and often it happens that our physical knowledge is 

 inadequate to explain the mechanical working of the organism ; 

 the phenomena are superlatively complex, the procedure is 

 involved and entangled, and the investigation has occupied but 

 a few short lives of men. When physical science falls short of 

 explaining the order which reigns throughout these manifold 

 phenomena, — an order more characteristic in its totality than any 

 of its phenomena in themselves, — men hasten to invoke a guiding 

 principle, an entelechy, or call it what you will. But all the while, 

 so far as I am aware, no physical law^, any more than that of 

 gravity itself, not even among the puzzles of chemical "stereo- 

 metry," or of physiological "surface-action" or "osmosis," is 

 known to be transgressed by the bodily mechanism. 



Some physicists declare, as Maxwell did, that atoms or mole- 

 cules more complicated by far than the chemist's hypotheses 

 demand are requisite to explain the phenomena of life. If what 

 is implied be an explanation of psychical phenomena, let the 

 point be granted at once ; we may go yet further, and decline, 

 with Maxwell, to believe that anything of the nature of physical 

 complexity, however exalted, could ever suffice. Other physicists, 

 like Auerbachf, or LarmorJ, or Joly§, assure us that our laws of 

 thermodynamics do not suffice, or are "inappropriate," to explain 

 the maintenance or (in Joly's phrase) the " accelerative absorption" 



* In a famous lecture (Conservation of Forces applied to Organic Nature, 

 Proc. Roy. lustit., April 12, 1861), Helmholtz laid it down, as "the fundamental 

 principle of physiology," that "There may be other agents acting in the living 

 body than those agents which act in the inorganic world; but those forces, as far 

 as they cause chemical and mechanical influence in the body, must»be quite of the 

 same character as inorganic forces : in this at least, that their effects must be ruled 

 by necessity, and must always be the same when acting in the same conditions; 

 and so there cannot exist any arbitrary choice in the direction of their actions." 

 It would follow from this, that, like the other "physical" forces, they must be 

 subject to mathematical anatysis and deduction. Cf. also Dr T. Young's Croonian 

 Lecture On the Heart and Arteries. Phil. Trans. 1809, p. 1: Coll. Works, i, .511. 



f Ektropismus, oder die physikalische Theorie des Lebens, Leipzig, 1910. 



J Wilde Lecture, Nature, March 12, 1908; ibid. Sept. 6, 1900, p. 485; 

 Aether and Matter, p. 288. Cf. also Lord Kelvin, Fortnightly Review, 1892, p. 313. 



§ Joly, The Abundance of Life, Proc. Roy. Dublin Soc. vii, 1890; and in 

 /Scientific Essays, etc. 1915, p. 60 et seq. 



