Page:Conservationofen00stew.djvu/223

 tion of carbon, hydrogen, etc.—that yields all the manifestations of power in the animal frame. And, in particular, it maintains (1) a certain warmth or temperature of the whole mass, against the cooling power of surrounding space; it maintains (2) mechanical energy, as muscular power; and it maintains (3) nervous power, or a certain flow of the influence circulating through the nerves, which circulation of influence, besides reacting on the other animal processes—muscular, glandular, etc. —has for its distinguishing concomitant the.

The extension of the correlation of force to mind, if at all competent, must be made through the nerve-force, a genuine member of the correlated group. Very serious difficulties beset the proposal, but they are not insuperable.

The history of the doctrines relating to mind, as connected with body, is in the highest degree curious and instructive, but, for the purpose of the present paper, we shall notice only certain leading stages of the speculation.

Not the least important position is the Aristotelian; a position in some respects sounder than what followed and grew out of it. In Aristotle, we have a kind of gradation from the life of plants to the highest form of