ORGANIC DEPENDENCE AND DISEASE 19 



cumulating dynamism. The parallel is a true one. The 

 insects branched into being from out of the scorpion stock 

 of the early Paleozoic age. Slowly they made their way 

 ahead, attaining the endowments of agility which life in the 

 air imparts; quick nerve reaction and refinement. Sud- 

 denly today they have reached a point where their intense 

 vitality is an actual menace to the mammal life on the earth, 

 whose future salvation seems in no small measure to be up 

 in the air between these insects and their aerial enemies, the 

 birds. The great reptilian bubble swelled up and burst in 

 the days of the Jurassic and Cretaceous periods, leaving 

 behind a few crocodiles and lizards for today, and that great 

 agile race of highest variability — the birds. The alligators 

 and salamanders and their scattered kin alone retain the 

 type of structure so painfully worked out through the long 

 ages before the days of the collapse and there is no chance, 

 not the faintest promise in the history of Nature that she 

 will, in such an earth as has now come into being, again 

 experiment with this type of structure. Out of the crash 

 of the reptilian overgrowth and extravagances only the 

 birds seem to have emerged with a promise still ahead. 

 Our own stock, the line down which we have come, travelled 

 clear of these excesses in development, and while the rep- 

 tilian blood is in mankind it is not that of the reptilian cli- 

 maxes, the dinosaur or the brontosaur. It is the surest 

 thing that the minorities of those ancient days saved the 

 day for us. And in the convulsion of ideas which has burst 

 upon the present world through the lifting of the lid to 

 pent-up and restrained bizarreries of impulse, there mil 

 remain behind, if Nature is true to her standards, a stal- 

 wart conservation of the type, minority though it may be, 

 which has been worked out through the ages and in which 

 must lie the enduring germ of future advance. The froth 

 is a scum of bubbles, the relief of a tension it is well to be 

 rid of. 



