too, when we find the brain of many animals unfurnished with ventricles? And supposing it were true that any kind of air or vapour was found there, seeing that all nature abhors a vacuum, still it does not seem over probable that it should be of heavenly origin and possessed of such superlative virtues. But what we admire most of all is that a spirit, the native of the skies, and endowed with such admirable qualities, should be nourished by our common and elementary air ; especially when we see it maintained that the elements can do nothing that is beyond their natural powers.
It is admitted, moreover, that the spirits are in a perpetual state of flux, and most readily dissipated and corrupted ; nor in- deed can they endure for an instant unless renovated by due supplies of their appropriate nutriment, they as much require incessant nourishing as the primum vivens, or first animate atom of the body. What occasion is there, then, I ask, for this ex- traneous inmate, for this ethereal heat ? when the blood is com- petent to perform all the offices ascribed to it, and the spirits cannot separate from the blood even by a hair's breadth without destruction; without the blood, indeed, the spirits can neither move nor penetrate anywhere as distinct and independent matters. And whether they are engendered and are fed and increased, as some suppose, from the thinner part of the blood, or from the primigenial moisture, as others imagine, all still confess that they are nowhere to be found apart from the blood, but are inseparably connected with it as the aliment that sustains them, even as the flame of a lamp or candle is inseparably connected with the oil or tallow that feeds it. The tenuity, subtilty, mobility, &c. of the spirits, therefore, bring no kind of advantage more than the blood, which it seems they constantly accompany, already possesses. The blood consequently suffices, and is adequate to be the immediate in- strument of the soul, inasmuch as it is everywhere present, and moves hither and thither with the greatest rapidity. Nor can it be admitted that there are any other bodies or qualities of a spiritual and incorporeal nature, or any more divine kinds of heat, such as light, as Caesar Cremoninus, 1 a great adept in the Aristotelian philosophy, strenuously contends against Albertus that there are.
1 Dictate vii.
