Page:Darwinism by Alfred Wallace 1889.djvu/445

 necessary to do this, in order that materials for the exercise of a selection should exist. Darwin and Wallace's law is then only restrictive, directive, conservative, or destructive of something already created. I propose, then, to seek for the originative laws by which these subjects are furnished; in other words, for the causes of the origin of the fittest."

Mr. Cope lays great stress on the existence of a special developmental force termed "bathmism" or growth-force, which acts by means of retardation and acceleration "without any reference to fitness at all;" that "instead of being controlled by fitness it is the controller of fitness." He argues that "all the characteristics of generalised groups from genera up (excepting, perhaps, families) have been evolved under the law of acceleration and retardation," combined with some intervention of natural selection; and that specific characters, or species, have been evolved by natural selection with some assistance from the higher law. He, therefore, makes species and genera two absolutely distinct things, the latter not developed out of the former; generic characters and specific characters are, in his opinion, fundamentally different, and have had different origins, and whole groups of species have been simultaneously modified, so as to belong to another genus; whence he thinks it "highly probable that the same specific form has existed through a succession of genera, and perhaps in different epochs of geologic time."

Useful characters, he concludes, have been produced by the special location of growth-force by use; useless ones have been produced by location of growth-force without the influence of use. Another element which determines the direction of growth-force, and which precedes use, is effort; and "it is thought that effort becomes incorporated into the metaphysical acquisitions of the parent, and is inherited with other metaphysical qualities by the young, which, during the period of growth, is much more susceptible to modifying influences, and is likely to exhibit structural change in consequence."

From these few examples of their teachings, it is clear that