10 PRINCIPLES OF ANIMAL BIOLOGY 



what to think. The clergy fostered this attitude, for they represented 

 authority, and Uved upon subservience. Obedience in intellectual as 

 well as religious matters was proffered as a matter of course. Contro- 

 versies upon insignificant matters, which could easily have been settled 

 by a few first-hand observations, were referred to the books of Aristotle 

 and others for decision. Those who chanced to make observations for 

 themselves, and then found something in their favorite writings which 

 seemed to refute their discoveries, refused to believe their own senses. 



The period of deference to authority lasted many centuries. During 

 this time interest in zoology was almost confined to the medical schools, 

 where, in the form of anatomy, it had a practical value. But even 

 anatomy was subject to the ills of the time. The works of Galen, 

 a famous anatomist of the second century (A.D.), were the authority 

 on which all teaching of anatomy was based. Galen himself was a 

 talented observer and forceful writer, and it is not occasion for surprise 

 that his works were accepted as the authority in questions of anatomy. 

 He worked under a handicap imposed by the customs of his time, 

 however, since human bodies could not then legally be dissected. As 

 substitutes, other animals were used, and wherever these animals differed 

 from man Galen was in error. In the absence of better works, Galen's 

 books were read from the lecturer's desk, with occasional demonstrations 

 of dissections — which, be it said, often belied the text they were supposed 

 to illustrate. The negation, however, was never noticed, or perhaps was 

 attributed to improper specimens for demonstration. 



The Revival. — Slavish acceptance of authority could scarcely do 

 other than breed revolt, and eventually prove its own undoing. Human 

 bodies became increasingly accessible for dissection. And so, after 

 more than a thousand years of servility, it is not surprising to find 

 Mondino da Luzzi, a professor at the University of Bologna, in Italy, 

 publishing in 1315 a work on human anatomy that was based, not on 

 Galen's books, but on dissection. He dissected as many as three human 

 bodies. Two hundred years later, Berengario, also of the University of 

 Bologna, dissected a hundred or more bodies, and presumably taught 

 anatomy from them. 



It was reserved, however, for Vesalius, a gifted Belgian, to make the 

 use of Galen's books alone unfashionable. Vesalius was a native of the 

 city of Brussels, where he was born in 1514. A portrait of him is repro- 

 duced in Fig. 2. He appears to have inherited a passion for learning 

 from an ancestry of physicians and scholars. His leaning was toward 

 anatomy, and in his boyhood, besides securing the traditional schooling in 

 Greek and Latin, he taught himself dissection, using the common animals 

 about him. On entering the University of Paris to study medicine, it 

 is said that he early became dissatisfied with the clumsy manner in which 

 demonstrations were made in the lectures, that he pushed aside the 



