ON LIFE AND ORGANISATION. 321 



It has been already stated that the immediate means of concep- 

 tion of breadth, or of extension in the transverse plane of the eye, 

 is primarily afforded by the mosaic structure of the retina. In like 

 manner, the means of conception of extension, in any direction, 

 cutting the transverse plane of the eye, is supplied by the position 

 of the eyes in front of the Human head. The Infant, when using 

 both eyes, contemplates two aspects of every solid object, or two 

 aspects of the entire scene before it. These two aspects afford two 

 pictures in planes at an angle to one another, and consequently con- 

 ceived of by its intelligence under different relations of space. It 

 involves in its combined conception of the object or scene all the 

 relations of Space, which are fundamental or necessary to its laws 

 of Thought. It conceives of the objects seen in the three rela- 

 tions of length, breadth, and depth. 



But, as the conceptions of the breadth and depth of an object 

 as primarily derived from the mosaic structure of the retina, are 

 extended and rendered more precise by the muscular movements 

 and sense of the eyeball and head ; so, in like manner, the full 

 advantage of the arrangements for binocular vision is dependent on 

 the use of the same means. 



But the most important accessory to the Human eye is the 

 Human hand. The Human hand is formed in absolute harmony 

 with the conditions of Human thought. It is an instrument ex- 

 pressly framed to act under it and for it. Psychologically con- 

 sidered, it is the principal channel through which we derive the 

 means of framing our conceptions of the form of bodies. Towards 

 this end, it co-operates with the eye, bringing to the aid of the lat- 

 ter the combined results of the sense of touch, highly developed, 

 on the fingers and palm, and of the muscular sense of the entire 

 limb. The peculiar manner in which the human thumb can be 

 opposed to the fingers, and the entire hand folded around the ob- 

 ject, as well as the specifically human manner in which the upper 

 limbs can embrace an object or enclose a space, arc, undoubtedly, 

 related to the requirements of the human self-consciousness. They 

 are tin; principal organical upmiis by which the human intelligence 

 reaches those motions of external objects, which, when thought 

 under the conditions of Space, enable it to frame its ('.(inceptions of 

 exti rnal nature. 



