110 CIRCULATION OF THE BLOOD. 



solid or excellent, nothing but foul terms, was to be expected 

 from them, so have I held them still less worthy of an answer. 

 Let them consume on their own ill nature; they will scarcely 

 find many well-disposed readers, I imagine, nor does God give 

 that which is most excellent and chiefly to be desired wisdom, 

 to the wicked; let them go on railing, I say, until they are 

 weary, if not ashamed. 



If for the sake of studying the meaner animals you should 

 even enter the bakehouse with Heraclitus, as related in Aris- 

 totle, I bid you approach ; for neither are the immortal Gods 

 absent here, and the great and almighty Father is sometimes 

 most visible in His lesser, and to the eye least considerable 

 works. 1 



In my book on the Motion of the Heart and Blood in Animals, 

 I have only adduced those facts from among many other obser- 

 vations, by which either errors were best refuted, or truth was 

 most strongly supported; I have left many proofs, won by 

 dissection and appreciable to sense, as redundant and unneces- 

 sary; some of these, however, I now supply in brief terms, 

 for the sake of the studious, and those who have expressed 

 their desire to have them. 



The authority of Galen is of such weight with all, that I 

 have seen several hesitate greatly with that experiment before 

 them, in which the artery is tied upon a tube placed within its 

 cavity ; and by which it is proposed to prove that the arterial 

 pulse is produced by a power communicated from the heart 

 through the coats of the arteries, and not from the shock of the 

 blood contained within them ; and thence, that the arteries dilate 

 as bellows, are not filled as sacs. This experiment is spoken of 

 by Vesalius, the celebrated anatomist ; but neither Vesalius nor 

 Galen says that he had tried the experiment, which, however, 

 I did. Vesalius only prescribes, and Galen advises it, to those 

 anxious to discover the truth, and for their better assurance, not 

 thinking of the difficulties that attend its performance, nor of 

 its futility when done ; for indeed, although executed with the 

 greatest skill, it supplies nothing in support of the opinion which 



1 [To those who hesitated to visit him in his kiln or bakehouse ('iTri'aj, which some 

 have said should be 'ITTTTW, rendered a dunghill) Heraclitus addressed the words in 

 the text. Aristotle, who quotes them, has been defending the study of the lower 

 animals. ED.] 



