THE PLEASURE OF VISUAL FORM. 783 



longed in space, or carried beyond the limits of ordinary and easy 

 muscular contraction. The movements of the eye will be found to 

 illustrate this law, though, owing to the small caliber of the ocular 

 muscles, both the enjoyment and the fatigue attending them are apt 

 to seem insignificant quantities. The pleasures of ocular movement 

 are thus confined within definite limits, namely, a certain duration of 

 a certain velocity of movement over the central part of the field of 

 vision. Further, movements involving a higher degree of muscular 

 expenditure grow fatiguing sooner than others, as we may see in the 

 case of following the outline of very near objects with convergent 

 axes. Finally, certain combinations of muscular action give rise to 

 fatigue sooner than others, e. g., those necessary to oblique movement 

 sooner than those involved in vertical or horizontal. The reason of 

 this may be not so much the larger number of muscular factors as the 

 relative infrequency of the combination. We have in a general way 

 much more need to execute vertical and horizontal movements than 

 oblique ones, height and lateral distance being the two most impor- 

 tant dimensions ; and this would tend to make the former easier and 

 less rapidly fatiguing. For a like reason, the superior ease of horizon- 

 tal movements may be referred in part to the greater need in general 

 of attending to lateral relations of distance than to vertical ones. 



Within these limits of pleasurable ocular movement we may find 

 a difference in the quality of the enjoyment, according as the move- 

 ment is energetic (though not excessively so) or comparatively restful. 

 In the first case the feeling is of a more active and stimulating quality, 

 and approaches in character the sense of power which we experience 

 when we employ the larger muscles of the body. In the second case 

 the feeling is more passive and allied to sensation proper. It may be 

 thrown out as a conjecture that the former mode of pleasurable feel- 

 .ing is connected with the excitation of the motor fibers, whereas the 

 latter consists mainly of the tactual and other sensations already re- 

 ferred to. We may, perhaps, conceive that, when the motor innerva- 

 tion reaches a certain degree of intensity, its mental correlative be- 

 comes the predominant feeling ; but that, when it falls below this 

 point, the passive sensations come to the surface of consciousness, so 

 to speak, and give the dominant character to the feeling. On the 

 whole, the gentler forms of ocular movement yield richer enjoyment 

 than the more energetic. The muscles of the eye hardly seem to be 

 of a sufficient caliber to supply the full consciousness of active force, 

 which is a concomitant of the energetic action of the larger muscles 

 of the body. Hence it may be said that the quieter forms of motor 

 enjoyment are preferred by the eye. 



This diffei-ence in the quality of the agreeable feelings of ocular 

 movement is best seen in comparing slow and rapid movements, as in 

 following the progress of a rocket in its early and later stages. As 

 Professor Bain remarks, rapid visible movements are stimulating, while 



