Those dreams that are troublesome, extravagant, whimsical, or unconnected, are commonly the effect of some confusion in his machine; such as painful indigestion--an overheated blood--a prejudicial fermentation, &c.--these material causes excite in his body a disorderly motion, which precludes the brain from being modified in the same manner it was on the day before; in consequence of this irregular motion the brain is disturbed, it only represents to itself confused ideas that want connection. When in a dream, he believes he sees a Sphinx, a being supposed by the poets to have a head and face like a woman, a body like a dog, wings like a bird, and claws like a lion, who put forth riddles and killed those who could not expound them; either, he has seen the representation of one when he was awake, or else the disorderly motion of the brain is such that it causes it to combine ideas, to connect parts, from which there results a whole without model, of which the parts were not formed to be united. It is thus, that his brain combines the head of a woman, of which it already has the idea, with the body of a lioness, of which it also has the image. In this his head acts in the same manner, as when by any defect in the interior organ, his disordered imagination paints to him some objects, notwithstanding he is awake. He frequently dreams, without being asleep: his dreams never produce any thing so strange but that they have some resemblance, with the objects which have anteriorly acted on his senses; which have already communicated ideas to his brain. The watchful theologians have composed, at their leisure, in their waking hours, those phantoms, of which they avail themselves, to terrify or frighten man; they have done nothing more than assemble the scattered traits which they have found in the most terrible beings of their own species; by exaggerating the powers, by enlarging the rights claimed by tyrants, they have formed ideal beings, before whom man trembles, and is afraid. Thus, it is seen, that dreams, far from proving that the soul acts by its own peculiar energy, that it draws its ideas from its own recesses; prove, on the contrary, that in sleep it is intirely passive, that it does not even renew its modifications, but according to the involuntary confusion, which physical causes produce in the body, of which every thing tends to shew the identity, the consubstantiality with the soul. What appears to have led those into a mistake, who maintained that the soul drew its ideas from itself, is this, they have contemplated these ideas, as if they were real beings, when, in point of fact, they are nothing more than the modifications produced in the brain of man, by objects to which this brain is a stranger; they are these objects, who are the true models, who are the real archetypes to which it is necessary to recur: here is the source of all their errors.