and essentially diverse. For as to abstract the idea of kind from that of degrees, which are alone designated in the language of common use, is the first and indispensable step in philosophy, so are we the better enabled to form a notion of the kind, the lower the degree, and the simpler the form is in which it appears to us. We study the complex in the simple; and only from the intuition of the lower can we safely proceed to the intellection of the higher degrees. The only danger lies in the leaping from low to high, with the neglect of the intervening gradations. But the same error would introduce discord into the gamut, et ab abusu contra usum non valet consequentia. That these degrees will themselves bring forth secondary kinds sufficiently distinct for all the purposes of science, and even for common sense, will be seen in the course of this inquisition: for this is one proof of the essential vitality of nature, that she does not ascend as links in a suspended chain, but as the steps in a ladder; or rather she at one and the same time ascends as by a climax, and expands as the concentric circles on the lake from the point to which the stone in its fall had given the first impulse. At all events, a contemptuous rejection of this mode of reasoning would come with an ill grace from a medical philosopher, who cannot combine any three phenomena of health or of disease without the assumption of powers, which he is compelled to deduce without being able to demonstrate; nay, even of material substances as the vehicles of these powers, which he can never expect to exhibit before the senses.
From the preceding it should appear, that the most comprehensive formula to which life is reducible, would
