Page:Physiological Researches upon Life and Death.djvu/36

 is to the functions of the organs what symmetry is to their conformation; it supposes a perfect equality of force and action, as symmetry indicates an exact analogy in the external forms and internal structure. It is a consequence of symmetry; for two parts essentially alike in their structure, cannot be different in their mode of acting. This plain reasoning will lead us to the general datum, that harmony is the character of the external functions, and that discoid is, on the contrary, the attribute of the organic functions; but upon this head it will be necessary to go into more ample detail.

We have seen that external life resulted from the successive actions of the senses, nerves, brain, and locomotive and vocal organs. Let us now consider the harmony of action, in each of these grand divisions.

The precision of our sensations appears to be so much the more perfect, as there happens to exist a more exact resemblance between the two impressions of which each is the assemblage. We see imperfectly when one of the eyes, better constituted and stronger than the other, is