ON LIFE AND ORGANISATION. 319 



consciousness. Duration and causation are conceptions impossible 

 for the animal intelligence ; neither can the relative conception of 

 space, or the secondary conceptions which flow from it, be possible 

 for a consciousness not conscious of self. 



As, however, these presumed distinctions between the conscious- 

 ness in man and in the brute are of primary importance in compara- 

 tive psychology, we shall proceed to inquire whether there is any 

 mode of procuring — not direct evidence, for, from the nature of the 

 subject, that is, as we have seen, beyond our reach — but cumulative 

 although indirect proof, such as must put the matter beyond 

 question. 



This matter cannot be discussed at length in this note. A 

 single example will suffice as an illustration of the method by 

 which the indirect evidence of the nature of the consciousness of 

 the brute may be attained. For this purpose the difference in 

 the modes in which the use of the organ of vision is acquired by 

 man, and by the lower animal, may be examined. 



In man every act of sensation or perception, although actually 

 occurring in the brain, is referred to the peripheral extremity of 

 the nerve filament excited, to which extremity the exciting object 

 is also referred (primarily), whether it acts on that extremity im- 

 mediately or mediately. 



Objects seen by the infant are, therefore, at first referred by it 

 to the peripheral part of the organ of vision — that is, to the eye- 

 ball. The sensation as well as the perception of the object are 

 both — if the expression may be allowed — located in or on the eye 

 itself. 



But the infant acquires the faculty of seeing objects not as 

 in contact with its own organism, but in their relative positions in 

 Space. This faculty is acquired by a process of investigation, the 

 results of which are retained by continued practice, while the steps 

 of the process by which they were originally procured have escaped 

 from the developing, and therefore comparatively weak memory of 

 the child. 



The explanation of this process involves the consideration of a 

 number of physiological and of psychological elements. The faculty 

 which the human being possesses of perceiving the relations of 

 objects in space, depends physiologically on the mosaic structure of 



VOL. I. Y 



