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 lias burst 
upon the present world through the lifting of the lid to 
pent-up and restrained bizarreries of impulse, there will 
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. 
