20 Transactions Liverpool biological society. 



the impacts of individual molecules, or small groups of 

 such? Most assuredly there are, for the Brownian motion 

 of bacteria in a liquid is a sight familiar to us all, and 

 we are pretty certain that ultra-microscopic organisms 

 exist, while mechanistic biology has even postulated the 

 existence of vital units, or biophors, consisting of 

 relatively few molecules. If then these organisms, 

 bacteria, or ultra-microscopic bodies, are able to utilise 

 the kinetic energy of molecules moving at velocities 

 greatly above the mean, we have a source of energy for 

 the chemical transformations effected by the nitrifying 

 bacteria. That these organisms should do so is not only 

 conceivable but the question is one for experimental 

 enquiry. If, for instance, we could show that in an 

 insolated growing culture of nitrifying bacteria the 

 temperature of the culture were to fall, we should have 

 an indirect proof. But then we should show clearly that 

 the second law of thermodynamics does not apply to the 

 organism, and that by the processes of life entropy can 

 be destroyed. 



Now all this consideration of the metabolism of the 

 plant and animal with reference to the laws of thermo- 

 dynamics has been necessary to show that the conception 

 of the organism as a physico-chemical mechanism fails, 

 and that close analysis of vital processes makes it fairly 

 certain that the functioning of plant and animal cannot 

 be described solely in terms of the concepts of matter and 

 energy employed in .experimental physics. A concept 

 peculiar to biology must be established, and thus we are 

 led to the consideration of the vital impetus of Bergson, 

 or the entelechy of Driesch. It is fair to state here that 

 perhaps most biologists will hesitate to admit this 

 necessity. I have followed, in the main, the arguments 

 of Bergson, but younger biologists should note that 



