THE UNIQUENESS OF LIFE 161 



to conquer by dividing it, for if one analyses it into its 

 components one inevitably misses the bond of union. . . . 

 The explanation of a biological fact cannot be obtained by 

 decomposing it, any more than the properties of a chemical 

 compound can be deduced from the properties of its consti- 

 tuent elements. ... A biological fact is something more 

 than a mere arbitrary assemblage of component physical and 

 chemical facts, and the component facts may be explained 

 without touching at all the problem of their composition. 

 In the case of the eel it is possible to decompose the act of 

 migration into a large number of acts of a different order, 

 into the chemical reactions occurring in muscular move- 

 ment, in nervous conduction, in the stimulation of peripheral 

 sense organs, but by doing so one cannot but lose sight of the 

 interconnection of these single acts, the interconnection which 

 really binds together all these acts into the single act of 

 migration. ... To decompose the act of migration 

 into an infinity of physico-chemical processes is to take an 

 infinity of little partial views of the act, but what one needs 

 for an explanation of the fact is a comprehensive view which 

 will unite all the relevant features of it into one picture. To 

 the chemist confronted with the problem there is no fact 

 of migration at all, there is only an intricate enravelment 

 of chemical reactions; to the biologist the fact of migration 

 to a particular region for a particular purpose is cardinal, 

 and the chemical processes involved in the action are neg- 

 ligible." 



But, it may be said, if the mechanistic description leaves 

 the eel's migration obscure, does any other description fare 

 better? The answer is that we must look at the migration 

 in the light of what we know of organisms in general. It 

 is certain, for instance, that what a living creature does 



