THE PHYSICAL BASIS OF LIFE 



By W. B. HARDY, M.A., F.R.S. 

 Fellow of Gonville and Caius College, Cambridge 



In a famous lay sermon on the Physical Basis of Life, written 

 nine years after the publication of The Origin of Species, Huxley 

 writes as follows : 



When hydrogen and oxygen are mixed in a certain pro- 

 portion and an electric spark is passed through them, they 

 disappear, and a quantity of water, equal in weight to the sum 

 of their weights, appears in their place. There is not the 

 slightest parity between the passive and active powers of the 

 water and those of the oxygen and hydrogen which have given 

 rise to it. At 32 , and far below that temperature, oxygen and 

 hydrogen are elastic gaseous bodies whose particles tend to 

 rush away from one another with great force. Water at the 

 same temperature is a strong though brittle solid, whose particles 

 tend to cohere into definite geometrical shapes. . . . 



Nevertheless, we call these and many other strange phe- 

 nomena the properties of the water, and we do not hesitate 

 to believe that in some way or another they result from the 

 properties of the component elements of water. We do not 

 assume that a something called "aquosity" entered into and 

 took possession of the oxide of hydrogen as soon as it was 

 formed, and then guided the aqueous particles to their places 

 on the facets of the crystal or amongst the leaflets of the hoar 

 frost. On the contrary, we live in the hope and in the faith that 

 by the advance of molecular physics we shall by-and-by be able 

 to see our way as clearly from the constituents of water to the 

 properties of water as we are now able to deduce the operations 

 of a watch from the form of its parts and the manner in which 

 they are put together. . . . 



If the properties of water may be properly said to result 

 from the nature and disposition of its component molecules, I 

 can find no intelligible ground for refusing to say that the 

 properties of protoplasm result from the nature and dis- 

 position of its molecules. 



But I bid you beware that, in accepting these conclusions, 

 you are placing your feet on the first rung of a ladder which, in 

 most people's estimation, is the reverse of Jacob's, and leads to 



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