ANIMAL INTELLIGENCE. 15 



company ing a muscular innervation apart from Uiat J'ccli)i<jr of the 

 act zvhich comes from seeing oneself move, from feeling one's 

 body in a different position, etc. It is the direct feeling of the 

 doing as distinguished from the idea of the act done gained 

 through eye, etc. For this reason I say ' impulse and act ' in- 

 stead of simply ' act .' Above all, it must be borne in mind that 

 by impulse I never mean the motive to the act. In popular speech 

 you may say that hunger is the impulse which makes the cat claw. 

 That will never be the use here. The word motive will always 

 denote that sort of consciousness. Any one who thinks that the 

 act ought not to be thus subdivided into impulse and deed may 

 feel free to use the word act for impulse or impulse and act 

 throughout, if he will remember that the act in this aspect of 

 being felt as to be done or as doing is in animals the important 

 thing, is the thing which gets associated, while the act as done, 

 as viewed from outside, is a secondary affair. I prefer to have 

 a separate word, impulse, for the former, and keep the word act 

 for the latter, which it commonly means. 



Starting, then, with its store of instinctive impulses, the cat 

 hits upon the successful movement, and gradually associates it 

 with the sense-impression of the interior of the box until the 

 connection is perfect, so that it performs the act as soon as con- 

 fronted with the sense-impression. The formation of each asso- 

 ciation may be represented graphically by a time-curve. In 

 these curves lengths of one millimeter along the abscissa repre- 

 sent successive experiences in the box, and heights of one milli- 

 meter above it each represent ten seconds of time. The curve is 

 formed by joining the tops of perpendiculars erected along the 

 abscissa i mm. apart (the first perpendicular coinciding with 

 the y line), each perpendicular representing the time the cat 

 was in the box before escaping. Thus, in Fig. 2 on page 18 

 the curve marked 12 in A shows that, in 24 experiences or trials 

 in box A, cat 12 took the following times to perform the act, 

 160 sec, 30 sec, 90 sec, 60, 15, 28, 20, 30, 22, 11, 15, 20, 

 12, 10, 14, 10, 8, 8, 5, 10, 8, 6, 6, 7. A short vertical line 

 below the abscissa denotes that an interval of approximately 24 

 hours elapsed before the next trial. Where the interval was 

 longer it is designated by a figure 2 for two days, 3 for three 



