tory of the vertebrate skeleton, and especially of the vertebrate shall, as the development of a "plan." This is the word he has selected, and which he uses over and over again. A plan—we must repeat—is not a mere pattern, which may arise by accident; it is a construction of which all the leading component elements are parts of one general conception having reference to a future. Such a plan, he tells us, can be traced and identified in all skulls, from the skull of a pike to the cranium of a man. The immense differences which mask this unity of plan are due to successive adaptive modifications, with which, in all their wide extent, the original plan was destined from the very first to work in harmony.
These are grand conceptions. They are scientific conceptions in the highest sense of that word, because they bring phenomena into harmonious relations with the highest faculties of the human mind. They are the conceptions which confer all its dignity and interest on geology, and on the affiliated sciences of paleontology and comparative anatomy. Although in one sense highly ideal, and in the best sense metaphysical, they are yet strictly literal, and absolutely true to fact. Hence Prof. Huxley most truly asserts that the doctrine of "all bony skulls being organized upon a common plan" is a simple generalization of the observed facts of cranial structure.[1] It is curious that many of those who use these conceptions for the purposes of description immediately turn round and repudiate them for the purposes of philosophy. But the language which embodies them can only be useful for the purposes of explanation by reason of the similitudes which they involve between our own mental operations and those which are obvious in nature. Yet these very similitudes and intellectual homologies are most distasteful to the agnostic school; and very often, even in the mere work of description, every device is resorted to to keep them out of sight. Thus some movements of the nervous and muscular apparatus in animals which involve the most complicated adjustments are constantly spoken of as mere "reflex action"—as if they could be compared with the mere reflection—or bending back—of light from water, or of sound from a wall. So again "differentiation" is perpetually used to describe the processes of preparation by which the building up of special organs is accomplished—just as if these wonderful processes could be described by a word which is equally applicable to the processes of corruption and decay. There is no disloyalty to truth so insidious as that which leads us to sin in this way against our own intellectual integrity. What our mind sees, we must confess to—at our peril. It may have been a brave thing in
- ↑ Comparative Anatomy, p. 278.
