Ill] OF CATALYTIC ACTION 255 



diffusion, some other activity to play the part of a regulatory 

 mechanism*. 



On growth and catalytic action 



In ordinary chemical reactions we have to deal (1) with a specific 

 velocity proper to the particular reaction, (2) with variations due 

 to temperature and other physical conditions, (3) with variations 

 due to the quantities present of the reacting substances, according 

 to Van't Hoff's "Law of Mass Action," and (4) in certain cases with 

 variations due to the presence of "catalysing agents," as BerzeHus 

 called them a hundred years agof. In the simpler reactions, the 

 law of mass involves a steady slo wing-down of the process as the 

 reaction proceeds and as the initial amount of substance diminishes: 

 a phenomenon, however, which is more or less evaded in the organism, 

 part of whose energies are devoted to the continual bringing-up of 

 supphes. 



Catalytic action occurs when some substance, often in very 

 minute quantity, is present, and by its presence produces or 

 accelerates a reaction by opening "a way round," without the 

 catalysing agent itself being diminished or used up J. It diminishes 

 the resistance somehow — little as we know what resistance means 



* According to the empirical canon of physiology, that, as Leon Fredericq 

 expresses it (Arch, rfc Zool. 1885), '*L'etre vivant est agence de telle maniere que 

 chaque influence pertyrbatrice provoque d'elle-meme la mise en activite de Tappareil 

 compensateur qui doit neutraliser et reparer le dommage." Herbert Spencer had 

 conceived a similar principle, and thought he recognised in it the vis medicutrix. 

 Nahirae. It is the physiological analogue of the "principle of Le Chatelier " (1888), 

 with this important difference that the latter is a rigorous and quantitative law, 

 ba8e<i on a definite and stable equilibrium. The close relation between the two is 

 maintained by Le Dantec {La titabilite de la Vie, 1910, p, 24), and criticised by 

 Lotka {Physical Biology, p, 283 seq.). 



t In a paper in the Berliner Jahrbuch for 1836, This paper was translated in 

 the Edinburgh New Philosophical Journal in the following year; and a curioas 

 little paper On the coagulation of albumen, and catalysis, by Dr Samuel Brown, 

 followed in the Edinburgh Academic Annual for 1840, 



X Such phenomena come precisely under the head of what Bacon called 

 Instances of Magic: "By which I mean those wherein the material or efficient 

 cause is scanty and small as compared with the work or effect produced; so that 

 even when they are common, they seem like miracles, some at first sight, others 

 even after attentive consideration. These magical effects are brought about in 

 three ways. . .[of which one is] by excitation or invitaticm in another body, as in 

 the magnet which excites numberless needles without losing any of its virtue, or 

 in yeast and such-like." Nov. Org,, cap. li. 



