To Professor Weismann the gratitude of naturalists is ever due for two excellent services. He it was who first taught us to distinguish the “soma”, or body, from the germ, thus ridding evolutionary science of the distracting belief that the experience of the organism is transmitted to its offspring. Formerly “use and disuse” were good enough answers to any troublesome conundrum of adaptation. Weismann's demand for evidence that in a single case such effects were transmitted brought this vague reasoning to an end. The inheritance of acquired characters was then seen to be an assumption needing independent proof, and, when proof was called for, there was no reply that a critical mind could accept as valid. How much laborious argumentation collapsed when this keystone was withdrawn we need not now recall; but those who are now constructing a sound science of heredity on the basis of physiological fact know that it was by Weismann's thorough demolition that their ground was cleared.

It was, moreover, through his ingenious speculations as to the mechanism of heredity that efforts were concentrated on a determination of the exact processes by which germ cells are formed. Whatever be the interpretation, the visible facts are now known, a direct consequence of Weismann's stimulus and initiative, which will bear fruit hereafter.

But even with this record well in mind, it is impossible to pass a lenient judgment on The Evolution Theory. It should have appeared thirty years ago. Then Natural Selection was a new idea.