Abernethy was generally very careful in these matters. I give one example. He is speaking of cartilage, or gristle, which covers the ends of the bones where they form joints, and has explained its great elasticity, the use of it in preventing jarring; and contrasted the springiness of youth with the easily jarred frame of age. "Well," he adds, "this cartilage is fibrous, and they say that the fibres are arranged vertically; so that the body may be said to be supported on 'myriads of elastic columns.'" That was the beauty by which he wished to impress that which he had previously taught.
When marvellousness is too much excited, many say, "Ah, how clever that gentleman is! what an interesting lecture! what a curious thing that was he showed us!" But when you inquire what principle or law was intended to be illustrated, you find that the sensual or the imaginative faculty has alone been excited, and has galloped off with that which was intended for the intellect. If persons are examined as to a particular point of the lecture, they are apt to say: "Well, that is just what I wanted to know; would you explain it?"
It would seem that it is a great mistake to excite marvellousness or our external senses very vividly, when we desire to concentrate the intellectual faculties. That breathless silence, with eyes and mouth open, that "intenti que ora tenebant" condition, excited by marvellousness, is very well for the story of Æneas, or Robinson Crusoe; but it is out of place, when we are endeavouring to augment our intellectual possessions.
We require, in fact, a calmer atmosphere. The desire to interest and hold the attention of our audience is so natural, that it is very apt to escape one that this may be done on terms not consistent with our real object—the interesting the intellect; and this fault is perhaps, of all, the worst; because it is never a greater failure than when it appears to be successful. All other faults in lecturing, if serious, in one respect tell their own tale in the thinning audience.
The learned author of the "Philosophy of Rhetoric" has observed that "A discourse directed to the understanding will not admit of an address to the passions, which, as it never fails to disturb the operation of the intellectual faculty, must be regarded by every intelligent hearer as foreign indeed, if not insidious." He had before said, "that in such a discourse you may borrow metaphor or comparison to illustrate it, but not the bolder figures, prosopopœia and the like, which are intended not to elucidate the subject, but to create admiration."
"It is obvious," he continues, "that either of the foregoing, far from being subservient to the main design (to address the intellect), serves only to distract the attention from it[67]."
This judicious writer, however, in the first sentence makes a distinction, which requires, perhaps, to be received with some caution.
There is no discourse that is solely intellectual; the driest mathematical proposition interests our feelings. The pleasure of truth, what is that? Not merely intellectual, certainly. It is a pleasure derived from the intellect, no doubt; but it is a feeling entirely distinct. So, in addresses to the passions, if they are successful, the presiding influence of the intellect is very obvious; this away, a discourse soon merges into bombast or fustian, a something which neither impresses the feelings nor the passions as desired.
The true desideratum, as it appears to us, is accuracy of adjustment, not separation. In intellectual operations, the feelings are to be subservient to the accomplishment of the objects of the intellect. In discourses, where the passions or feelings are most appealed to, or most prominent, the intellect must still really guide, though it may appear to follow.
Notwithstanding that so much of Abernethy's lecturing was on anatomy, and therefore necessarily addressed to the eye, yet he seldom offered any illustration to the external senses. He was always endeavouring to impress the mechanical arrangement of parts, by reference to their uses and surgical relations. Even in speaking of light, he would be suggestive beyond the mere perception of sense. He used to say, of refraction of light, when the refracting medium was, as it commonly is, the denser body, "that the ray seems as if attracted"—a very suggestive phrase to any one who has thought much on the subject of light. It is a curious thing to observe how confused the ideas of many people are on phenomena of light; and we are afraid that the cause is, that the illustrations to the eye are given too soon. If people were made to understand by a simple illustration what they are about to see, it is probable they would have much clearer ideas. The intellect having gone before, the eye no longer diverts it from its office; and the eye would then be merely impressing, by means of a physical representation, an established idea.