VESALIUS AND THE NEW ANATOMY 27 



Vesalius, fully occupied as court physician, was no longer 

 in a position to make new physiological or anatomical 

 observations. The second edition of the work, though 

 distinctly an improvement on the first, does not therefore 

 exhibit many facts that he had not already recorded. It 

 does, however, contain certain changes in point of view 

 that were very important for the subsequent development 

 of physiology. In the second edition of his great book 

 Vesalius no longer merely hints his doubts as to the 

 character of Galen's physiology, he openly asserts that 

 he is unable to verify its fundamental bases. He was 

 now in a strong position as the personal attendant of a 

 powerful and orthodox monarch. He could therefore 

 say what he meant with comparatively little fear or 

 risk. 



We may take a single instance of this new outspoken- 

 ness. In his description of the septum of the heart he 

 had written in the first edition : The septum of the 

 ventricles is formed from the very densest substance of 

 the heart. It abounds on both sides with pits imprinted 

 on it, by reason of which it is provided with an uneven 

 surface towards the ventricles. Of these pits none, so 

 far as the senses can perceive, penetrate from the right 

 to the left ventricle. We are thus forced to wonder at 

 the art (industria) of the Creator by which the blood 

 passes from right to left ventricle through pores which 

 elude the sight." This passage is altered to something 

 quite different in the second edition, where he writes : 

 4 Although sometimes these pits are conspicuous, yet 

 none, so far as the senses can perceive, passes from the 

 right to the left ventricle. ... I have not come across even 

 the most hidden channels by which the septum of the 

 ventricles is pierced. Yet such channels are described 

 by teachers of anatomy who have absolutely decided that 

 blood is taken from the right to the left ventricle. I, 



