OG 



POPULAR RCIES'IIFIC I.IXTUKES. 



wish to regard myself us open to instruction 

 by those more experienced than myself. 



The physiological study of the manner in 

 which the perceptions of our senses origi- 

 nate, how impressions from without pass into 

 our nerves, and how the condition of the lat- 

 ter is thereby altered, presents many points of 

 contact with the theory of the fine arts. On 

 a former occasion I endeavored to establish 

 tiuch a relation between the physiology of 

 the sense of hearing and the theory of music. 

 Those relations in that case are particularly 

 'lrur and distinct, because the elementary 

 f ir-ns of ninsi<> depend more closely on liie 

 nature and on the peculiarities ot our percep- 

 tions than is the case in other arts in which 

 the nature of the material to be used and of 

 the objects to be represented has a far greater 

 influence. Yet even in those other branches 

 of art, the especial mode of perception of 

 that organ of sense by which the impression 

 is taken xip is not without importance ; and 

 a theoretical insight into its action, and into 

 the principle of its methods cannot bo com- 

 plete if this physiological element is not taken 

 into account. Next to music this seems to 

 predominate more particularly in painting, 

 and this is the reason why I have chosen 

 painting as the subject of my present lecture. 

 The more immediate object of the painter 

 is to produce in us by his palette a lively 

 visual impression of the objects which he 

 has endeavored to represent. The aim, in a 

 certain sense, is to produce a kind of optical 

 illusion ; not indeed that, like the birds who 

 pecked at the painted granes of Apelles, we 

 are to suppose we have present the real ob- 

 jects themselves, and not a picture ; but in 

 BO far that the artistic representation produces 

 in us a conception of their objects as vivid 

 and as powerful as if we had them actually 

 before us. The study of what are called il- 

 lusions of the senses is, however, a very prom- 

 inent and important part of the physiology 

 of the senses ; for just those cases in which 

 external impressions evoke conceptions 

 which are not in accordance witli reality are 

 particularly instructive for discovering the 

 laws of those means and processes by which 

 normal perceptions originate. We must 

 look upon artists as persons whose observa- 

 tion of sensuous impressions is particularly 

 vivid and accurate, and whose memory for 

 these images is particularly true. That which 

 long tradition has handed down to the men 

 most gifted in this respect, and that which 

 they have found by innumerable experiments 

 in 'the most varied directions, as regards 

 means and methods of representation, forms 

 a series of important and significant facts, 

 vhich the physiologist, who has here to learn 

 rom the artist, cannot afford to neglect. The 

 tady of works of art will throw great light 

 the question as to which elements and re- 

 of our visual impressions are most 

 iominant in determining our conception 

 is seen, and what others are of lass 

 ice. As far as lies within his power, 

 will seek to foster the former at the 

 : latter. 



In this sense, then, a careful observation of 

 the works of the great masters will bo ser\ u-c- 

 able, not only to physiological optics, but 

 also because the investigation of the laws of 

 the perceptions and of the observations ot 

 the senses will promote the theory of art. 

 that is, the comprehension of its mode of 

 action. 



We have not hero to do with a discussion 

 of the ultimate objects and aims of art, but 

 only with an examination of the action of 

 the elementary means with which it works. 

 The knowledge of the latter must, however, 

 form an indispensable basis for the solution 

 of the deeper questions, if we are to under- 

 stand the problems which the artist has to 

 solve, and the mode in which he attempts to 

 attain his object. 



I need scarcely lay stress on the fact, fol- 

 lowing as it does from what I have already 

 said, that it is not my intention to furnish 

 instructions according to which the artist is 

 to work. I consider it a mistake to suppose 

 that any kind of aesthetic lectures such an 

 these can ever do so ; but it is a mistaka 

 which those very frequently mako who have 

 only practical objects in view. 



I. FORM. 



The painter seeks to produce mhispictnr* 

 an image of external objects. The first aim of 

 our investigation nmst be to ascertain \vhnt 

 degree and what kind of similarity he can 

 expect to attain, and what limits are assigned 

 to him by the nature of his method. The 

 uneducated observer usually requires nothing 

 juore than an illusive resemblance to nature : 

 the more this is obtained, the more does ho 

 delight in the picture. An observer, on tho 

 contrary, whose taste in works of art has 

 been more finely educated, will, consciously 

 or unconsciously, require something more, 

 and something different. A faithful copy of 

 crude nature he will at most regard as an ar- 

 tistic feat. To satisfy him, he wi'l need ar- 

 tistic selection, grouping, and even idealiza- 

 tion of the objects represented. The human 

 figures in a work of art must not bo the 

 every-day figures, such as we see in photo- 

 graphs ; they must have expression, and a 

 characteristic development, and if possible 

 beautiful forms, which have perhaps belonged 

 to no living individuals, or indeed any in- 

 dividuals which over have existed, but only 

 to such a one as might exist, and as must 

 exist, to produce a vivid perception of any 

 particular aspect of human existence in it* 

 complete and unhindered development. 



If, however, the artist is to produce an ar- 

 tistic arrangement of only idealized types, 

 whether of man or of natural objects, luunt 

 not the picture be an actual, complete, and 

 directly true delineation of that which wo\ild 

 appear if it anywhere camo into being? 



Since the picture is on a plane surface, 

 this faithful representation can of course 

 only give a faithful perspective view of tho 

 objects. Yet our eye, which in its optical 

 properties is equivalent to a camera obscura, 

 the well-known apparatus of the photogra- 



