1913] BOWER—SIR JOSEPH HOOKER 301 
essential features in the problem, together with the changes of 
climate, such as have determined the advance and retrocession of 
glacial conditions. Having noted these factors, he continued thus: 
“With the establishment of the doctrine of orderly evolution 
of species under known laws, I close this list of those recognized 
principles of the science of geographical distribution, which must 
guide all who enter upon its pursuit. As HumBoLpT was its 
founder, and Forses its reformer, so we must regard DARWIN as 
its latest and greatest lawgiver.’’ Now, after thirty years, may 
we not add to these words of his, that HOOKER was himself its 
greatest exponent ? 
You will have felt how tenuous is the line of limitation, if line 
indeed there be, between morphological reality and- morphological 
abstraction; between the unit observed, and the summation of such 
units into a progression; between the static and the dynamic study 
of living things. It was this line that was crossed by Darwin; 
and, as I have shown, Hooker was the first of his friends to follow. 
To the general public he was perhaps the least known of the great 
triumvirate of Glasgow. The results he achieved do not touch 
everyday life so nearly as those of KELvin or of Lister. This is 
perhaps natural, for while he was the leading botanist of his time, 
he was, before all, a philosopher. In him we see the foremost stu- 
dent of the broader aspects of plant life at the time when evolution- 
ary belief was nascent. His influence at that stirring period, 
though quiet, was far-reaching and deep. His work was both 
critical and constructive. His wide knowledge, his keen insight, 
his fearless judgment were invaluable in advancing that intellectual 
revolution which found its pivot in the mutability of species. The 
share he took in promoting it was second only to that of his life- 
long friend, CHARLES DARWIN. 
UNIversITy or GLASGOW 
