As for astronomy, study all the rules thereof.

Let pass, nevertheless, the divining and judicial astrology, and the art of Lullius, as being nothing else but plain abuses and vanities.

As for the civil law, of that I would have thee to know the texts by heart, and then to confer them with philosophy.
Now, in matter of the knowledge of the works of nature, I would have thee to study that exactly, and that so there be no sea, river, nor fountain, of which thou dost not know the fishes; all the fowls of the air; all the several kinds of shrubs and trees, whether in forests or orchards; all the sorts of herbs and flowers that grow upon the ground; all the various metals that are hid within the bowels of the earth; together with all the diversity of precious stones that are to be seen in the orient and south parts of the world.

Let nothing of all these be hidden from thee.

Then fail not most carefully to peruse the books of the Greek, Arabian, and Latin physicians, not despising the Talmudists and Cabalists; and by frequent anatomies get thee the perfect knowledge of the other world, called the microcosm, which is man.