3 i2 THE POPULAR SCIENCE MONTHLY. 



So, again, if the child is at fault, he does not think of the meaning 

 of the sentence, and of what is wanted to complete it ; but " tries 

 back" over the preceding words, that their sound may suggest that 

 of the word he desiderates. So there are older persons, with whom 

 the pictured remembrance of the words and phrases is more sugges- 

 tive ; as in a case to be presently cited. Now, in these instances, it is 

 a familiar fact that what is thus learned but once, however perfectly, 

 soon " goes out of the head," being only fixed there by continual rep- 

 etition ; and, as the Memory we are now considering is rather Sensorial 

 than Ideational, this fact is confirmatory of the doctrine that seems 

 probable on other grounds, of the superior (if not the exclusive) per- 

 sistence of the latter. We seem distinctly able to trace the action 

 of the recording process in this elementary form of Memory, in the 

 help given in the " learning by heart " of a task, by repeating it the 

 last thing at night ; for every school-boy, who has to commit to mem- 

 ory fifty lines of Virgil, knows very well that, if he can " say them to 

 himself," even slowly and bunglingly, just before going to sleep, he 

 will be able to recite them much more fluently in the morning. The 

 Physiologist sees here an obvious indication that the recording process 

 has gone on without interruption by new impressions on the Sensori- 

 um, so that there has been time for the fixation of the last by Nutritive 

 chano-e. We have, indeed, a remarkable converse phenomenon, in the 

 rapid fading away of a Dream, which, at the moment of waking, we 

 can reproduce with extraordinary vividness ; for the " trace " left by 

 its details is soon obliterated by the new and stronger impressions 

 made on our waking Consciousness, so that, a few hours afterward, 

 we are often unable to revive more than the general outline of the 

 Dream and perhaps not even that, unless we have told it to another 

 when it was fresh in our minds, of which act a "trace " would be left. 



There are two classes of persons who are professionally called upon 

 for great temporary exercises of Memory, viz., Dramatic Performers 

 and Barristers. An actor, when about to perform a new " part," not 

 only, commits it to memory, but " studies" it, so as to make it part of 

 himself; and all really great actors identify themselves for the time 

 with the characters they are performing. When a " part " has once 

 been thoroughly mastered, the performer is usually able to go through 

 it, even after a long interval, with very little previous preparation. But 

 an actor is sometimes called upon to take a new " part " at very short 

 notice ; he then simply " learns it by heart," and speedily forgets it. 

 A case of this kind is cited by Dr. Abercrombie, as having been the 

 experience of a distinguished actor, on being called on to prepare 

 himself in a long and difficult part, at a few hours' notice, in conse- 

 quence of the illness of another performer. He acquired it in a very 

 short time, and went through it with perfect accuracy ; but immediately 

 after the performance forgot it to such a degree that, although he 

 performed the character for several days in succession, he was obliged 



