No. 606] 



BIOLOGICAL ENIGMAS 



329 



completely satisfactory general theory of the process 

 could be formulated. In this state of affairs, the use of 

 the conception as a general explanatory agent in biology, 

 could not be said to establish an unequivocal bond be- 

 tween biological regulation and the theory of matter. At 

 the present day, however, it is ]:)ossible to frame a hy- 

 pothesis to account for catalytic action, which has general 

 applicability and at the same time rests directly upon the 

 ideas of modern molecular physics. 



Ostwald defines a catalytic agent as ''a substance which 

 changes the velocity of a reaction witliout itself lieing 

 changed by the process."^" In tlic older tcniiiiiolouv of 

 the pioneer, Berzelius, it is '"a sult-taiicc wiiidi. incrcly 

 by its presence and not throuuh its altinity, lias the ]i()wer 

 to render active alTinities which are latent at ordinary 

 temperatures."^" According to Ostwald, catalytic power 

 is a universal property of matter, for he says : 



Tliivlx^inu the enM'. it dioiihl often oeeur that a Mib^tance 

 will cataiN/e a rea<'lioii which ii('iierate> further (|uan- 



nu-iilal o! i\u tUM nMatinudiip.. and that rea^on^ .-an be 

 adduced t'oi- rcuardin-anto.-atalvtic pouer a^ a necc^^ary 

 property of every complex fi)rni of matter. 



Perhaps the >imiile>t illn>tration of a catalytic effect 

 of any sort is tliat of the prothiction of crystallization in 

 a supersaturated solution of some sul)stance hy the intro- 

 duction of a small crystal of the same substance. This 

 of course ha> the form of an r////rM-at;i 1\ lie ]froce--. Al- 

 though effects of this kind are InchuhMl in ( Mwald's 

 classification of varieties of catalysis, i'' u)) to ivcent times 



i« Mollor, loc. cit., 250. 

 17 Ihid., 24G. 

 18 254. 



