The space of time which cows, sheep, and other animals go with young is always the same, and their deliveries are not attended with an hæmorrhage. May we not then conclude, that the blood voided by women after delivery is the menstrual blood, and that the human foetus being born at such different terms, can only be by the actions of this blood on the matrix during every periodical revolution? It is natural to imagine, that if the females of viviparous animals had menses like women, their deliveries would be followed with an effusion of blood, and happen at different terms. The foetuses of animals come into the world clothed with their membranes (and it seldom happens that the membranes are broken), and the waters flow before the delivery; whereas it is very rare a child is brought forth with its membranes entire. This seems to prove that the human foetus makes more efforts than other animals to quit its prison; or that the matrix of a woman does not so naturally incline to the passage of the child, for it is the foetus which tears its membranes, by the efforts it makes against the resistance it meets with at the orifice of the viscera. RECAPITULATION. All animals procure nutriment from vegetables, or other animals which feed upon vegetables; there is, therefore, one common matter to both, which serves for the nutrition and expansion bf every thing which lives or vegetates. This matter cannot perform them but by assimilating itself to each part of the animal or vegetable, and by intimately penetrating the texture and form of these parts, which I have called the _internal mould_. When this nutritive matter is more abundant than is necessary to nourish and expand the animal or vegetable, it is sent back from every part of the body, and deposited in one or more reservoirs, in the form of a liquor; this liquor contains all the molecules analogous to all parts of the body; and consequently all that is necessary for the reproduction of a young being, perfectly resembling the first. Commonly this nutritive matter does not become superabundant, in most kinds of animals, till they have acquired the greatest part of their growth; and it is for this reason that animals are not in a state of engendering before that time. When this nutritive and productive matter, which is universally spread abroad, has passed through the internal mould of an animal or vegetable, and has found a proper matrix, it produces an animal or vegetable, of the same kind; but when it does not meet with a proper matrix, it produces organized beings different from animals and vegetables, as the moving and vegetating bodies seen in the seminal liquor of animals, in the infusion of the germ of plants, &c.