DEVELOPMENTS IN PHILOSOPHY OF BIOLOGY 



8$ 



no necessity need be felt for a complete 

 abandonment of mechanical explanation 

 in this case. If the specific heat of the 

 reactants and resultants of a chemical 

 reaction is known, the equilibrium con- 

 stant can be calculated by the use of 

 Nernst's equation. Now if the equilib- 

 rium constant of the reaction H 2 2 = 

 H 2 + O catalysed by the enzyme catalase 

 be calculated it works out at io 18 - 4 from 

 which it may be concluded that not izo 

 atmospheres but billions of atmospheres 

 would be required to suppress the pro- 

 duction of oxygen from hydrogen peroxide 

 by the enzyme catalase. With this most 

 interesting demonstration there collapses 

 one of the most formidable of the objec- 

 tions on which the neo-vitalists have been 

 accustomed to rely. Haldane (zi) has 

 recently given a historical review of the 

 famous controversy about secretion and 

 nitration of oxygen in the human lung, 

 and concludes still, as against Barcroft, 

 that only the secretion-theory can explain 

 the facts of acclimatization to life at high 

 altitudes. These questions give addi- 

 tional significance to Roughton's cal- 

 culation. 



REGULATION IN LIVING MATTER 



The finalism associated with living 

 beings is nowhere more insistently evident 

 than in their unswerving maintenance of 

 steady states. The living organism has 

 as it were a certain niche in its physico- 

 chemical surroundings, and to that it will 

 always return provided that the disturbing 

 influence has not been so great as to throw 

 it out of gear altogether. Its normal 

 hydrogen ion concentration, its normal 

 osmotic pressure, its normal concentration 

 of glucose or salts, its normal physiologi- 

 cal constants, these it will always tend to 

 preserve unchanged. The purposiveness 

 with which it clings to this equilibrium 

 has to be disregarded altogether as such 



in the application of the scientific method 

 to life phenomena, for teleology is not a 

 concept in any way congruent with 

 measurement. An interesting attempt has 

 indeed been made by Lillie (3Z) to give 

 biological purposiveness a quantitative 

 expression by regarding it as a special case 

 of equilibrium, namely between organism 

 and environment, and so applying to it 

 an extended form of the principle of 

 LeChatelier. In spite of Lillie's excellent 

 discussion, however, in which the balance 

 between the constructive and constitutive 

 on the one hand and the destructive and 

 dissipative tendencies in living things on 

 the other are so well set forth, it is still 

 extremely uncertain whether the concept 

 of teleology can be translated into me- 

 chanical terms. It is more likely that 

 these principles are inherently antipathe- 

 tic. Probably they cannot with advan- 

 tage be mixed. 



But the phenomena of regulation of 

 steady states in living things may be 

 approached from a purely scientific angle. 

 The importance of buffer action was amply 

 appreciated by Lawrence Henderson, and 

 it will be remembered that in the preface 

 to his book The Fitness of the Environment he 

 says that he was led to those considera- 

 tions by researches on the special proper- 

 ties of solutions of phosphates and borates. 

 Buffer action, indeed, must be regarded 

 as a most important factor in organic 

 regulation. The phenomena of oxidation- 

 reduction potential have been also much 

 studied of recent times, and here again 

 systems have been discovered in which an 

 addition of one of the reactants produces 

 a minimum change in the state of the sys- 

 tem as a whole. Such conditions are dis- 

 cussed in the papers of Mansfield Clark and 

 his colleagues (6), and to the phenomenon 

 Clark has given the name ' 'poising action' ' 

 to indicate its similarity to buffer action 

 in the case of hydrogen ion concentration. 



