34 o THE POPULAR SCIENCE MONTHLY. 



six, or seven times, during the same brief visit. Everybody knows 

 the archbishop's flavor of apoplexy in the memory as in the other men- 

 tal powers. I was once asked to see a woman who had just been in- 

 jured 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 hap- 

 pened?' '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 mem- 

 bers of those worshiping assemblies whose favorite hymn is l We 

 won't go home till morning.' Is memory then," he proceeds, " a ma- 

 terial record ? Is the brain, like the rock of the Sinaitic Valley, writ- 

 ten 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 corre- 

 sponding 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 ac- 

 cords 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, 



