_VASARI expressly mentions Leonardo's anatomical studies, having had
occasion to examine the manuscript books which refer to them.
According to him Leonardo studied Anatomy in the companionship of
Marc Antonio della Torre_ "aiutato e scambievolmente
aiutando."_--This learned Anatomist taught the science in the
universities first of Padua and then of Pavia, and at Pavia he and
Leonardo may have worked and studied together. We have no clue to
any exact dates, but in the year 1506 Marc Antonio della Torre seems
to have not yet left Padua. He was scarcely thirty years old when he
died in 1512, and his writings on anatomy have not only never been
published, but no manuscript copy of them is known to exist._

_This is not the place to enlarge on the connection between Leonardo
and Marc Antonio della Torre. I may however observe that I have not
been able to discover in Leonardo's manuscripts on anatomy any
mention of his younger contemporary. The few quotations which occur
from writers on medicine--either of antiquity or of the middle ages
are printed in Section XXII. Here and there in the manuscripts
mention is made of an anonymous "adversary"_ (avversario) _whose
views are opposed and refuted by Leonardo, but there is no ground
for supposing that Marc Antonio della Torre should have been this
"adversary"._

_Only a very small selection from the mass of anatomical drawings
left by Leonardo have been published here in facsimile, but to form
any adequate idea of their scientific merit they should be compared
with the coarse and inadequate figures given in the published books
of the early part of the XVI. century.

William Hunter, the great surgeon--a competent judge--who had an