iigS LIFE : OUTLINES OF GENERAL BIOLOGY 



millions of years the rich world of hfe. Not by the unpacking of 

 something given at the outset, but by a unique creativeness, there 

 has been a ceaseless emergence of the new, a succession of tentatives 

 that sometimes blazed a fresh path, yet sometimes led nowhere. 

 Without haste, without rest, new patterns were woven, and it may 

 have taken half a million years to fashion a feather. It is not that 

 one type of animal was transformed into another, that would be 

 magic; it was rather that an old type produced variants which 

 continued the new departure in their offspring — a process that went 

 on until, perhaps, a new position of stability was secured. Th^ new 

 and the old seem often to have lived together, or the new may have 

 pushed on into an unoccupied area. Gradually, however, in most 

 cases, the old order changed, giving place to the new. We can study 

 these new departures or variations to-day, sometimes small and 

 fluctuating — the Proteus creeps; sometimes large and brusque — the 

 Proteus leaps. Modern Biology gives us glimpses of Natura saltatrix 

 with daring experiments in self-expression. And through it all there 

 is the winnowing of the struggle for existence — sometimes rough, 

 often subtle, a winnowing that is never random, but is in relation 

 to an already woven web of life or system of inter-relations. It is 

 this discriminate sifting in relation to what has been already estab- 

 lished that prevents retrogression, except in parasites and the like, 

 and that allows of the separation not merely of the sheep from the 

 goats, but of those saying Shibboleth from those who can only say 

 Sibboleth. And we miss part of the secret of Evolution if we do not 

 realise that the organism is not a passive item sifted in a callous 

 mesh; it is an elbowing living creature, determined to play its own 

 hand of hereditary cards. It trades with time and trafficks with 

 circumstance. 



The broadest fact is the most eloquent of aU, that as age succeeded 

 age there emerged creatures with more fullness and freedom of life, 

 and with increasing expression of mind. Before there were any 

 backboned animals there were backboneless animals; and similarly 

 fishes gave rise to amphibians, and amphibians to reptiles, and 

 reptiles to birds and mammals, until at last arose the man. There 

 have been strange eddies in the stream of life, often hauntingly 

 beautiful; there have been culs-de-sac or blind alleys on the path 

 of life, leading to nothing higher, as in the case of sponges; there have 

 even been retrogressions, as in the case of parasites and sedentary 

 animals; but organic evolution has been, on the whole, what man 

 must caU progressive. If this word is too human in its implication 

 some other of similar significance must be invented. The trend of 

 organic evolution is towards integration, that is to say towards 

 creatures that are more harmonised, unified, and controlled than 

 their predecessors. 



As is painfully obvious, the term evolution is overworked, for it is 



