ZOOLOGY EMERGES 49 



Andreas Vesalius (1514-1560), by reforming anatomy 

 and thus placing morphological study on a new plane, 

 stands closest related to zoology. His great illus- 

 trated work on the structure of the human body 

 (De Fabrica Humani Corporis, 1543), based entirely 

 on observation, not only restored anatomy but at 

 the same tune laid the foundations for the structural 

 studies of animals. On account of the wide influence 

 of this book of Vesalius', published in 1543, we must 

 recognize it as one of the milestones of biological 

 progress. It was his method of direct investigation 

 that produced the greatest results. 



Previous to Vesalius anatomy had been expounded 

 from the desk chiefly by readings from Galen, a 

 celebrated physician of the fourth century A. D. 

 The strict adherence of Vesalius to observations and 

 faithfully drawn sketches from actual dissections 

 not only corrected many of Galen's statements but 

 overthrew authority as a source of knowledge and 

 replaced it by observation. 



Some years later (about 1619) William Harvey, 

 who is known for his discovery of circulation of the 

 blood (1628), introduced experimental observation 

 into scientific investigation. Thus the method of 

 science was reestablished and, on the basis of ob- 



