DEVELOPMENTS IN PHILOSOPHY OF BIOLOGY 



dealt with by the scientific method. 

 Summed up as it is in Wordsworth's "We 

 murder to dissect" organicism is certainly 

 far from characteristic of the scientific 

 mind. 



LIVING MATTER AND THERMODYNAMICS 



The relations of living systems to the 

 law of entropy have been considered again 

 and again during the last fifty years, and 

 now very recently the question has been 

 reopened by F. G. Donnan. That living 

 things should be in some way exempt from 

 the otherwise universal law that free 

 energy tends always to decrease in amount 

 in the known universe and entropy to 

 increase, has many times been asserted, 

 though without any evidence. The earli- 

 est hint of this is found in the writings of 

 Lord Kelvin, then Sir. W. Thomson, who 

 said as long ago as 185Z "It is impossible 

 by means of inanimate material agency to 

 derive mechanical effect from any porti on of 

 matter by cooling it below the temperature 

 of the coldest of surrounding objects" (5Z). 

 Thus, as Guye says, Thomson was already 

 making reservations on the applicability 

 of Carnot's principle to the mechanism of 

 living systems. Then in i88z H. von Helm- 

 holtz (24) definitely suggested that living 

 cells might have some way of eluding 

 Carnot's principle. In a paper read be- 

 fore the Berlin Academy of Sciences on 

 February z of that year he said in a 

 footnote, referring to the impossibility 

 of any increase of free energy: "Whether 

 such a change would also be impossible in 

 the fine structure of living organized tissue 

 appears to me still to be an open question, 

 the importance of which in the economy 

 of nature is very obvious . ' ' 



Here there was already the hint of the 

 mechanism by means of which this might 

 be done. The appreciation of the sta- 

 tistical nature of the second law, gave it, 

 however, much greater precision. James 



Johnstone (Z9) and G. N. Lewis (31) more 

 recently both decided that living things 

 and living things alone can retard the 

 accumulation of entropy. Now obviously 

 the most astonishing things may be 

 hidden by statistical treatment. Some- 

 where in the universe water may run 

 uphill, though as a whole, and in general, 

 it does not do so. The treatment of men 

 on a statistical basis furnishes results of 

 great value, but there we know directly 

 and by observation how individual the 

 individual is. This may be also the case 

 with molecules, and it is a commonplace 

 that to an intelligence such as a Clerk- 

 Maxwell demon they may have very 

 pronounced individuality. As G. N. 

 Lewis says, there is certain astronomical 

 evidence that indicates the existence of 

 disentropic phases in the universe, phases 

 in which the amount of bound energy 

 is diminishing instead of increasing; it is, 

 therefore, equally possible that in the 

 living body there are also phases where 

 the statistical second law does not truly 

 apply. That living plants retard the 

 accumulation of entropy by storing free 

 energy is undeniable, but that any living 

 system ever reverses this process is another 

 matter. Nevertheless both Johnstone and 

 Lewis regard it as the main characteristic 

 of life, as does Driesch (13), who says 

 "Es gibt seine Damonen. Wir selbst 

 sindsie!" 



In 1919 Guye (17) devoted some space 

 to the examination of this question. He 

 showed clearly that the high efficiency of 

 physiological systems in no way proved 

 that they functioned contrary to Carnot's 

 principle, But rather that they were not true 

 heat engines, a fact quite well appreciated 

 by physiologists. He also demonstrated 

 that the retardation of entropy-increase by 

 the green plant was a process that could be 

 paralleled in several non-living systems, 

 for instance, the evaporation of the oceans. 



