Io BIONOMIC LAWS. 
whether the evolution of species is anything more than a doubtful 
hypothesis. In other words, it may be thought that the attempt to 
explain the method of evolution before it has been proved that there 
is such a process is an inversion of logical method. Further consid- 
eration will, however, show that the greatest obstacle to the general 
acceptance of the theory of evolution has been the difficulty in believ- 
ing that this wonderful transformation is being wrought out in our 
very presence, and that the laws in accordance with which it pro- 
gresses are in a large degree open to investigation. 
The possibility of recognizing this stupendous reality has been shut 
out of the mind by the double assumption that the methods of crea- 
tion are necessarily inscrutable and that the process of creation has 
been closed never to be reopened. As both these assumptions are 
without proof, the shortest method of setting them aside is to show 
that the energies of creation are ever working in the ordinary pro- 
cesses of life. The effectiveness of this general method of appeal to 
actual experience and observation is seen in Darwin’s ‘‘Origin of 
Species.”’ He there first shows that a process of breeding, which in 
domestication always results in divergent varieties, is also being car- 
ried on by natural causes. He then shows that if we assume that 
species have been produced, one from another, by some such process, 
the relations of species to species, not only in the groups of scientific 
classification, but also in their geographical distribution over the 
earth and in their geological successions in time, become intelligible, 
and present a network of interrelated and significant phenomena, the 
causes of which can be more or less fully traced. I propose to follow 
the same general method. But as present debate relates to the prin- 
ciples and causes on which evolution depends rather than to the proof 
that such evolution has taken place, I shall give my chief attention 
to the first part of the argument. I shall discuss the forms and laws 
of bionomic action by which the relations of species to species are 
being maintained or modified, and shall refer to the results of this 
action as revealing the nature of the process. 
3. Need of Investigation of all the Forms of Interaction causing 
Transformation. 
Inquiries leading to the discovery of bionomic laws have usually 
been first suggested by observing the relations under which organ- 
isms present themselves as distributed in nature; but after we have 
once recognized the fact that these relations are the result of the 
constant interaction between organism and organism, and between 
the organism and the physical environment, it becomes necessary to 
