that the definition of any one of them, as that of anger for example, may be said to be the motion of a body of particular nature, or part or function of a body, by such a cause, and for such an end.
Thus, for these reasons, it is for the physiologist to study the Vital Principle, either as a whole, or under some particular manifestation. But the physiologist and the metaphysician would differ widely in their definition of any one of those emotions, as that of anger, for example; which, while the latter would hold to be desire for retaliation, or some such motive, the former would maintain to be ebullition of blood, or excess of heat about the heart. The one of these, in fact, accounts for the passion by the matter, and the other by the form and cause; for the form is the cause of the thing, which, if it is to be, must, of necessity, be in a special matter. Thus, the cause of a house, for instance, is such as this—"to be a shelter to avert injury from rain, wind, and heat;" and here the physiologist will speak of stones, bricks, and rafters, while the metaphysician will, in these materials, only behold the form to be adopted for those purposes. Which, then, of these is the physiologist? Is it he who studies only the matter without reference to the cause, or he who is occupied with the cause only? Or is it rather he who judges both from cause and matter; and which of the two is he? May we not however rather say that there is one who is
