110 PROF. BOWER : 
deeply ingrained belief inithe Constancy of Species. This doctrine, intro- 
duced originally by Linnæus as a summation of his experience, was for a 
century accepted by his followers as established truth. But, on the other 
hand, there was a growing sense of the kinship of living organisms. 
“Natural Affinity ” was instinctively recognized as a consequence of close 
comparison. The instinct translated itself into methods of grouping together 
such forms as have prominent features in common into genera and families. 
Such relationship and consequent grouping was exemplified in all divisions 
of the Vegetable Kingdom. If this was merely a reflection of the plan of 
separate Creation of Constant Species, well might Elias Fries remark that 
there was ** quoddam supernaturale” in the Natural System. 
The fact is that the doctrines of independent creation, and of constancy 
uf species are incompatible with the idea of affinity in the ordinary sense of 
the word. This was doubtless in the minds of the Systematists of the early 
19th Century. But many of them, like Sir William Hooker, were content to 
expend their labour upon the recognition and record of those * affinities,” 
without raising the inconvenient question of causality. Such difficulties 
vanished with the collapse of the doctrine of Constancy of Species, and 
the establishment of the theory of Evolution through Mutability. The 
results already achieved in Natural Classification then found a new inter- 
pretation. Affinity was held to mean some degree of relationship by 
Descent. A Natural Classification, if correctly constructed, would then 
be understood to visualise what remains of the evidences of Genetic History. 
In fact, Classification and Phylesis should coincide. 
The question may, however, be asked by those concerned especially in 
Systematic Work, whether convenience is to be wholly ignored in the 
systematic arrangements in use at the present day. It has been seen that 
Sir William Hooker still admitted that convenience of application should 
modify the method he used in the ‘Species Filicum.’ Therein he, as a 
Pre-Darwinian, continued the practice which underlay, in more or less 
degree, all the antecedent Artificial Systems. A very real object before 
the early writers was readiness of identification of species believed to be 
distinct, though in some way related. An insistent question for us now, 
in the light of Evolutionary Belief, is whether or not convenience is 
still to be allowed to modify the systematic exposition of phyletie con- 
clusions, so as to render identification practically easy? The answer 
should be a resolute negative. This is, indeed, the only answer for those 
who clearly see in Systematic Arrangement a reflection of Genetic History. 
But still some degree of convenience can be gained without the violation 
of affinities demonstrated by more minute analysis. When such demon- 
stration has been given, it should still be possible to construct analytical 
keys, which would serve for ready systematic identification, without 
involving all of the exacting observations of the laboratory. But in writing 
