Book 5
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DEMOCRITUS says that dreams are formed by the illapse of adventitious representations. Strato, that the irrational part of the soul in sleep becoming more sensible is moved by the rational part of it. Herophilus, that dreams which are caused by divine instinct have a necessary cause; but dreams which have their origin from a natural cause arise from the soul’s forming within itself the images of those things which are convenient for it, and which will happen; those dreams which are of a constitution mixed of both these have their origin from the fortuitous appulse of images, as when we see those things which please us; thus it happens many times to those persons who in their sleep imagine they embrace their mistresses.
Chapter III. OF THE NATURE OF GENERATIVE SEED.
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ARISTOTLE says, that seed is that thing which contains in itself a power of moving, whereby it is enabled to produce a being like unto that from whence it was emitted. Pythagoras, that seed is the sediment of that which nourisheth us, the froth of the purest blood, of the same nature as the blood and marrow of our bodies. Alcmaeon, that it is a part of the brain. Plato, that it is the deflux of the spinal marrow. Epicurus, that it is a fragment torn from the body and soul. Democritus, that it proceeds from all the parts of the body, and chiefly from the principal parts. as the flesh and muscles.
Chapter IV. WHETHER THE SPERM BE A BODY.