and undisguised. He who takes medicine is ill advised.
[Footnote: This appears to be a sketch for a poem.]
856.
I teach you to preserve your health; and in this you will succed better in proportion as you shun physicians, because their medicines are the work of alchemists.
[Footnote: This passage is written on the back of the drawing Pl.
CVIII. Compare also No. 1184.]
XV .
Astronomy.
Ever since the publication by Venturi in 1797 and Libri in 1840 *of some few passages of Leonardo's astronomical notes, scientific astronomers have frequently expressed the opinion, that they must have been based on very important discoveries, and that the great painter also deserved a conspicuous place in the history of this science. In the passages here printed, a connected view is given of his astronomical studies as they lie scattered through