All this belongs, roughly speaking, to the side of the matter which regards popular theology; but there is another side which is connected more especially with the New Learning. This other school, which sought to bring the somewhat elastic elements of the magical theory of the universe into the semblance of a systematic whole, is associated with such names as those of Paracelsus, Cornelius Agrippa, and the Abbot von Trittenheim. The fame of the first named was so great throughout Germany that when he visited any town the occasion was looked upon as an event of exceeding importance.[18] Paracelsus fully shared in the beliefs of his age, in spite of his brilliant insights on certain occasions. What his science was like may be imagined when we learn that he seriously speaks of animals who conceive through the mouth, of basilisks whose glance is deadly, of petrified storks changed into snakes, of the stillborn young of the lion which are afterwards brought to life by the roar of their sire, of frogs falling in a shower of rain, of ducks transformed into frogs, and of men born from beasts; the menstruation of women he regarded as a venom whence proceeded flies, spiders, earwigs, and all sorts of loathsome vermin; night was caused, not by the absence of the sun, but by the presence of the stars, which were the positive cause of the darkness. He relates having seen a magnet capable of attracting the eyeball from its socket as far as the tip of the nose; he knows of salves to close the mouth so effectually that it has to be broken open again by mechanical means, and he writes learnedly on the infallible signs of witchcraft. By mixing horse-dung with human semen he believed he was able to produce a medium from which, by chemical treatment in a retort, a diminutive human being, or _homunculus_, as he called it, could be produced. The spirits of the elements, the sylphs of the air, the gnomes of the earth, the salamanders of the fire, and the undines of the water, were to him real and undoubted existences in nature.