six, or seven times, during the same brief visit. Everybody knows the archbishop's flavor of apoplexy in the memory as in the other mental powers. I was once asked to see a woman who had just been injured in the street. On coming to herself, 'Where am I? What has happened?' she asked. 'Knocked down by a horse, ma'am; stunned a little; that is all.' A pause, 'while one, with moderate haste, might count a hundred;' and then again, 'Where am I? What has happened?' "Knocked down by a horse, ma'am; stunned a little; that is all.'" (Mr. Holmes appears to have sympathized with the patient's mental condition.) "Another pause, and the same question again; and so on during the whole time I was by her. The same tendency to repeat a question indefinitely has been observed in returning members of those worshiping assemblies whose favorite hymn is 'We won't go home till morning.' Is memory then," he proceeds, "a material record? Is the brain, like the rock of the Sinaitic Valley, written all over with inscriptions left by the long caravans of thought, as they have passed year after year through its mysterious recesses? When we see a distant railway-train sliding by us in the same line, day after day, we infer the existence of a track which guides it. So, when some dear old friend begins that story we remember so well—switching off at the accustomed point of digression; coming to a dead stop at the puzzling question of chronology; off the track on the matter of its being first or second cousin of somebody's aunt; set on it again by the patient, listening wife, who knows it all as she knows her well-worn wedding-ring—how can we doubt that there is a track laid down for the story in some permanent disposition of the thinking-marrow?"
We seem to recognize here a process of change in the brain corresponding to that which takes place in the body with advancing years—the induration of its substance, so that it loses flexibility, and thus, while readily accomplishing accustomed work, is not readily adapted for new work. Our old proverb, "You can't teach an old dog new tricks," indicates, coarsely enough, but justly, the peculiarity, as well mental as bodily, to which I refer. There is not a loss of power, but a loss of elasticity. We see aged men working well in the routine work to which they have been accustomed, but failing where there is occasion for change either of method or of opinion. Again, one recognizes this peculiarity in the scientific worker, whence perhaps we may regard it as a fortunate circumstance that the tendency of the aged mind accords with its faculties, so that old men do not readily undertake new work. Perhaps no more remarkable instance could be cited of the combination I refer to—the possession of power on the one hand, and the want of elasticity on the other than the remarkable papers on the universe, written by Sir W. Herschel, in the years 1817 and 1818, that is, in his seventy-ninth and eightieth years. We find the veteran astronomer proceeding in the path which, more than forty years before,
