Mechanistic Biology 24 1 



distinct from either mind or soul, is present in living matter, 

 eternally watchful to destroy his carefully planned experiments and 

 to escape from his observation. Moreover, if a graph were drawn 

 having as its ordinate the progress made in mechanistic explana- 

 tions and as its abscissa the last fifty years, a curve would result 

 unmistakably showing the continual defeat of vitalism. One 

 would have only to extrapolate the curve to find the date at which 

 complete mechanistic explanation of bodily life should first become 

 possible. As, however, the shape of the curve also depends on 

 " constraint of Princes, barratry of Master and Mariners, and Acts 

 of God," we shall here decline the task and proceed to consider a 

 few other points relative to the argument from inconceivability. 



To return to Haldane's quotation. " The cell-nucleus must 

 carry within it," he says, " a mechanism by which reaction with 

 the environment not only produces the millions of complex and 

 delicately balanced mechanisms which constitute the adult organism, 

 but provides for their orderly arrangement into tissues and organs." 

 The neo-vitalists are fond of drawing stupendous pictures of the 

 complexity of living stuff, and of inviting appropriate meditations 

 upon it. But they neglect Poincare's famous dictum about the 

 hierarchy of facts. To listen to the neo-vitalists one would think 

 that mechanistic descriptions were useless unless they accounted 

 for the movements of every single molecule in every single cell. 

 The complexity of living cells everyone must admit to be enormous, 

 but it is a belief of the biochemist that there are certain key-factors 

 and vantage-points which enable us to gain a general view over 

 large tracts. For example, the regulation of the exact intensity of 

 acidity in animal tissues is one of the processes to which the neo- 

 vitalists point as inexplicable ; yet the ^Journal of Biological 

 Chemistry is full of accurate descriptions of the mechanisms by 

 which this is effected. It is a fact in chemistry that if an acid and 

 a salt are present in concentrations about equal, then the addition 

 of more acid or more base is needed to upset the system than if 

 their concentrations were very different. This is called " buffer 

 action," and it is one of the key-positions referred to above. It 

 must play a part in the regulation of numberless systems in the cell. 

 Granted that development and acidity- regulation are extraordinarily 

 complicated processes, nevertheless in biochemistry we are con- 

 tinually coming upon key discoveries which bring at once in their 

 train the explanation of a hundred other facts. The intensely 



