512 
ISLAND LIFE. 
[part II. 
of the earth, but such apparently unimportant facts as the 
presence of certain types of plants or animals in one island 
rather than in another, are now shown to be dependent on the 
long series of past geological changes — on those marvellous 
astronomical revolutions which cause a periodic variation of 
terrestrial climates — on the apparently fortuitous action of 
storms and currents in the conveyance of germs — and on the 
endlessly varied actions and reactions of organised beings on 
each other. And although these various causes are far too 
complex in their combined action to enable us to follow them 
out in the case of any one species, yet their broad results are 
clearly recognisable ; and we are thus encouraged to study more 
completely every detail and every anomaly in the distribution 
of living things, in the firm conviction that by so doing we shall 
obtain a fuller and clearer insight into the course of nature, and 
with increased confidence that the “ mighty maze ” of Being 
we see everywhere around us is “ not without a plan.” 
