reading of poetry opens the eyes to a new world of phenomena, obvious indeed, but not actually observed until we receive this sort of aid. An appropriate instance in illustration of my meaning, may be found in the set of phrases employed by medical practitioners for characterizing the variations of the PULSE: for this example shows how very much the exactness of our perceptions depends upon the mental aid we receive from the use of distinctive terms. An unprofessional finger, how fine soever may be its sense of touch, does not usually discriminate more than four or five varieties of beat, at the wrist; and we are content to say that the pulse isquick or slowhard or softstrong or weak. But the varieties noted by the physician, and retained in his recollection by the use of distinctive epithets, amount to as many as two and twenty. As for instance, the pulse is said to be eitherfrequent, slow, intermittent, equal, regular, or of varying force: or it isfull, long, labouring, bounding, feeble: or it ishard, sharp, strong: or it iswiry, weak, soft, yielding: or it isquick, or tardy: or it islarge, or small. Now by the mere aid of this set of phrases, fixed in the memory, an unprofessional hand might be trained, with a little practice, to feel and to distinguish all these varieties. Descriptive words, then, and especially technical terms, might justly be called the antennæ of perception: it is by these that we feel our way toward nicer, and still more nice sensations.
Or let any one give a few days’ attention to a botanical glossary, storing his memory, pretty well, with those phrases which have been constructed for the purpose of noting what common eyes do not discriminate, in the forms and colours of the vegetable world. The mere possession of these words enables him to see what, without them, he would never have noticed. We now put out of view the regularly conducted and scientific study of botany, and borrow an illustration from it, with the single intention of
