The corrugators, by their contraction, lower the eyebrows and bring them together, producing vertical furrows on the forehead—that is, a frown. Sir C. Bell, who erroneously thought that the corrugator was peculiar to man, ranks it as “the most remarkable “muscle of the human face. It knits the eyebrows “with an energetic effort, which unaccountably, but “irresistibly, conveys the idea of mind.” Or, as he elsewhere says, “when the eyebrows are knit, energy of “mind is apparent, and there is the mingling of thought “and emotion with the savage and brutal rage of the “mere animal.” There is much truth in these remarks, but hardly the whole truth. Dr. Duchenne has called the corrugator the muscle of reflection but this name, without some limitation, cannot be considered as quite correct.

A man may be absorbed in the deepest thought, and his brow will remain smooth until he encounters some obstacle in his train of reasoning, or is interrupted by some disturbance, and then a frown passes like a shadow over his brow. A half-starved man may think intently how to obtain food, but he probably will not frown unless he encounters either in thought or action some difficulty, or finds the food when obtained nauseous. I have noticed that almost everyone instantly frowns if he perceives a strange or bad taste in what he is eating.