136 SCIENCE PROGRESS 



mechanist in biology, that the more mechanism he could detect the less the 

 possibility of an extra-mechanical agent. He might correct this notion by re- 

 flecting that complexity and completeness of mechanical organisation are often 

 due to intelligent — to extra-mechanical — agents. This is the vitalist's reply to the 

 statement quoted above and to the mechanist's formidable list of the physico- 

 chemical accomplishments of the organism. There is more mechanism in the 

 weaving of cloth in Britain to-day than in primitive weaving without looms. The 

 mechanism of travel is more perfect, more diffused, and infinitely more elaborate 

 to-day than when the first navigator paddled his tree-trunk with a branch. The 

 range of mechanism, in the sphere of human invention, increases with the range 

 of intelligence. The vitalist justly remarks that, by analogy, the very complexity 

 and extent of mechanism in the organism indicates an extra-mechanical agency. 

 On this point, as on others, the difficulties of deciding the problem grow with 

 research. The mechanist continues to discover more physics and more chemistry 

 in the organism — nicer and more complex adjustments in the living thing. This 

 success constantly arouses the hope that the organism will ultimately be 

 exhaustively analysed into physics and chemistry, and the always pertinent 

 vitalistic reply that, the more complex and delicate the mechanism the more 

 probable the existence of the X — the extra-mechanical factor. 



The mechanist secures no victory by concentrating the controversy on the egg. 

 Loeb remarks that " the cytoplasm contains the rough preformation of the 

 embryo," and, in commenting on some vitalistic views, refers to the importance of 

 the structure and heterogeneity of the unfertilised egg^. The study of enzyme 

 action has given a further disclosure of the mechanism, or possible mechanism, of 

 development. Suppose, for the sake of argument, that the fertilised egg-cell is 

 a connected collection of enzymes. Development then proceeds from their sys- 

 tematised co-ordinated activity — as they operate at their appropriate times and in 

 their appropriate places. The problem presented by a host of physico-chemico 

 activities co-operating as a whole towards a certain result — the structure and 

 functioning of the organism in its life-activities— is not seriously altered by 

 throwing the whole burden on a big collection of tiny enzymes. The enzymes are 

 the whole of the organism according to the mechanist— at all events the materials 

 on which they act and the forces they apply fall within the physico-chemico 

 sphere. The vitalist can easily reply that the enzymes behave like chemists who 

 serve the extra-mechanical agency— even if he is compelled to add they are 

 chemists of its own making. They act so appropriately, so in conjunction, that 

 they suggest control and controller as surely as the mechanism of a battleship 

 suggests an artificer. Modern battleship gunfire is almost completely mechanical, 

 and it is " almost " precisely because it is not quite. It would not be difficult for 

 the planetary observer to overlook the factor represented by the gun-control 

 officer — it is easy to overlook the organising agency in the impressive organisation 

 of the enzymes rendered liberally automatic. 



An absolutely exhaustive analysis of the organism might settle the question for 

 or against mechanism. Such exhaustive analysis is not yet, to say nothing of the 

 difficulty of deciding when the limit of analysis is reached. Meanwhile, no 

 multiplication of the organism's purely physico-chemico performances can decide 

 the issue. Loeb resolves a number of animal tropisms into physico-chemico 

 circuits. Heliotropism, he claims, can be connected in many cases with the 

 Roscoe-Bunsen law that the chemical effects of light vary with the product of 

 the time and illumination intensity. " Apparent instincts," he remarks, " in some 

 cases obey simple physicochemical laws with almost mathematical accuracy." 



