32. Besides, there is not a shadow of probability in what written by Vallesius and quoted from him by us (_Vide supra nº 30_); and I wonder that any thing so extravagant should have fallen from the pen of such a learned man. Medical men are well aware that the size of the fetus depends, not indeed on the quantity of matter, but on the quantity of virtue, that is to say of spirits held by the sperm; there lies the whole secret of generation, as is well observed by Michael Ettmuller, _Institut. Medic. Physiolog._: “Generation”, says he, “entirely depends upon the genital spirit contained within an envelope of thicker matter; that spermatic matter does not remain in the uterus, and has no share in the formation of the fetus; it is but the genital spirit of the male, combined with the genital spirit of the female, that permeates the pores, or, less frequently, the tubes of the uterus, which it fecundates by that means.” Of what moment can therefore the quantity of sperm be for the size of the fetus? Besides, it is not always a fact that men thus begotten by Incubi are remarkable for the huge proportions of their body: Alexander the Great, for instance, who is said to have been thus born, as we have mentioned, was very short; as the poet said of him: _Magnus Alexander corpore parvus erat._ Besides, although it is generally a fact that those who are thus begotten excel other men, yet such superiority is not always shown by their vices, but sometimes by their virtues and even their morals; Scipio Africanus, for instance, Cæsar Augustus and Plato the Philosopher, as is recorded of each of them respectively by Livy, Suetonius and Diogenes Laertius, had excellent morals. Whence may be inferred that, if other individuals begotten in the same way have been downright villains, it was not owing to their being born of an Incubus, but to their having, of their own free will, chosen to be such.