THE BIOLOGY OF THE CELL SURFACE 



to living matter; but the synthesis of protein-like bodies, 

 of sugar and of fat as well as the synthesis of thyroxin 

 (a compound in the internal secretion of the thyroid gland), 

 of products of other internal secretions and of vitamins must 

 dissipate whatever belief may have lingered on since 

 Wohler's classic synthesis of urea (more than a hundred 

 years ago) that some unknown vital principle sets apart 

 the chemistry of living things from that of non-living. 



And yet there is a difference which expresses itself in the 

 chemical make-up of the living thing. It is its organiza- 

 tion.^ The difference with respect to chemistry thus lies 

 in the peculiar combination of compounds which together 

 make a heterogeneous system. This acts as a unit-struc- 

 ture, whose behavior or manifestations are those of a single 

 thing and not the sum-total of the multitudinous chemical 

 components in an agglomerate mass. 



Living matter has an organization peculiar to itself. 

 Nowhere except in the living world does matter exhibit this 

 organization. Life, even in the simplest animal or plant, 

 so far as we know, never exists apart from it. Resting 

 above and conditioned by non-living matter, life perhaps 

 arose through the chance combination of the compounds 

 which compose it. But who knows 1 A living thing is not 

 only structure but structure in motion. As static, it 

 reveals the superlative combination of compounds of 

 matter; as a moving event, it presents the most intricate 

 time-pattern in nature. Life is exquisitely a time-thing, 

 like music. And beyond the plane of life, out of infinite 

 time may have come that harmony of motion which 

 endowed the combination of compounds with life. 



Clearly then, the state of being alive reposing in com- 

 binations, in the order in which the constituents are 



1 Dujardin, iSjj; Brucke, iS6i; Jllman, iSyg; Verzvorn, iSgg; 

 Moore, ig2i. 



2 



