FUNCTIONS OF ANIMAL LIFE. 



stantly bounds the operations of the most powerful intellect, and the highest 

 flights of the imagination. That in a future state of heing the communion of 

 mind with mind will be more intimate, and that Man will be admitted into more 

 immediate converse with his Maker, appear to be alike the teachings of the 

 most comprehensive philosophical inquiries, and of the most direct Revelation 

 of the Divinity. 



103. The Organs of Sense are instruments which are adapted to enable 

 particular nerves to receive impressions from without ; of a kind, and in a 

 degree, of which they would not otherwise be sensible. Thus, although the 

 simple contact of a hard body with the nerve may be readily conceived to pro- 

 duce a material change in it, of such a kind as would be easily propagated to 

 the central sensorium, it is evident that a nerve must be peculiarly modified 

 to receive and conduct sonorouS impressions from the undulations of the air ; 

 still more-^-to be susceptible of the impressions produced by the undulations 

 of that ethereal medium, to the vibrations of which most Natural Philosophers 

 now attribute the transmission of light. And, even when this difficulty has 

 been provided for by some modification in the structure of the nerve itself, 

 there is evidently another still remaining, that of understanding how distinct 

 images of the form, colour, &c., of external objects can be communicated to 

 the nerve of sight, or ideas of the direction, pitch, quality, &c., of sono- 

 rous undulations, can be obtained through the auditory nerve. There is reason 

 to believe that many among the lower Animals, which do not see objects around 

 them, are conscious of the influence of light ; and thus the distinction between 

 the mere reception of the impression, and the communication of the optical 

 image, becomes evident. The former may take place through the intervention 

 of nerves, whose sensory extremities offer no peculiarities : the latter can only 

 be received through the medium of an instrumenf/which shall, from the mix- 

 ture of rays falling equally upon every part of a surface, produce an optical 

 image, and then impress it upon the expanded surface of the nerve ; so that 

 each fibril may receive a distinct impression, the image presented to the mind 

 being formed by the combination of the whole. That this is, in fact, the share 

 which the organs of special sense bear in the general endowments of the whole 

 apparatus, may be inferred especially from the conformation of the Eye, which 

 is in every respect a merely optical instrument of the greatest beauty and per- 

 fection, adapted to present to the nerve, in the most advantageous manner, the 

 images of surrounding objects in all their variations; and we might conceive 

 that, if it were possible for the interior of the living eye to be replaced by one 

 constructed of inorganic materials by the hand of man, and for the retina to 

 preserve its functional activity, the pow r er of sight would be but little impaired, 

 except through the incapability, on the part of any piece of human mecha- 

 nism, to imitate those wondrous contrivances of Infinite Skill, which have for 

 their object the adaptation of the instrument to varieties of distance, of intensity 

 of light, &?c. There can be little doubt that the structure of the Ear is arranged 

 to do the same for the sonorous vibrations which the eye does for the rays of 

 light; that is, through its means, the undulations which strike upon the 

 external surface of the organ are separated and distinguished, those of a like 

 kind being brought together upon one division of the nerve, and those of 

 another order upon a different set of fibres; so that the different kinds of sound, 

 and the peculiar quality and direction of each, may be discriminated ; whilst, 

 by the concentration of all the impressions of the same character, a higher 

 amount of force is given to them. Of the sense of Smell, no similar account 

 can be given; since the medium by which odours are propagated is not known. 

 If, as is generally believed, this is accomplished by the diffusion through space 

 of minute particles of the odoriferous body itself (which supposition seems to 

 derive support from the general fact, that the most volatile substances are 



