32 THE PHYSICAL BASIS OF LIFE 



lis is able to translate this into intelligible language'? We 

 say pedantically — and no doul)t correctly — that the 

 orderly operation of the cell results from a dynamic 

 equilibrium in a polyphasic colloidal system (p. 8). In 

 our mechanistic treatment of the problem we commonly 

 assume this equilibrium to be somehow traceable to an 

 original pattern or configuration of material particles 

 in the system, as is the case with a machine. Most cer- 

 tainly conceptions of this type have given us an indis- 

 pensable working method — the method which almost 

 alone is responsible for the progress of modern biology — 

 but the plain fact remains that there are still some of the 

 most striking phenomena of life of which it has thus far 

 failed to give us more than the most rudimentary under- 

 standing. Foremost among these stand the phenomena of 

 development, which more than any others bring home to 

 us the nebulous state in wdiich the whole concept of or- 

 ganization still remains. When the organism has come to 

 full development it consists of co-ordinated parts, which 

 display a multitude of cunning devices — anatomical, 

 physiological or chemical — that make provision for the 

 harmonious co-operation of its activities for its protec- 

 tion and maintenance. To this extent its organization is 

 obvious and intelligible; and to the same extent the or- 

 ganism is clearly a j^iece of mechanism, a living machine. 

 But let us review the building of this machine by follow- 

 ing it backward, step by step, to its starting point. Step 

 by step we find the intricate machinery of life vanishing 

 before our eyes until nothing remains but a single cell, the 

 egg (Fig. 14). In this cell, complex though it may be in 

 its own way, not a trace seems to remain of the co-ordinat- 

 ing and unifying devices of the adult ; but who will main- 

 tain that the egg is not as specifically organized and as 

 truly alive as the adult to which it gives rise ? 



