14 GENERAL PRINCIPLES OF ZOOLOGY. 



to making the human cadaver a subject of scientific in- 

 vestigation. 



Middle Ages. The first thousand years in which Chris- 

 tianity formed the ruling power in the mental life of the 

 people was even for anatomy quite fruitless; in the main 

 they held to the writings of Galen and the works of his 

 commentators, and only seldom took occasion to prove 

 their correctness by their own observations. With the 

 ending of the Middle Ages the interest in independent 

 scientific research first broke its bounds. 



Vesal (1514-1564), the creator of Modern Anatomy, 

 had the courage to carefully investigate the human cadaver 

 and to point out in Galen's writings numerous errors which 

 had arisen through the unwarranted application to human 

 anatomy of the discoveries made upon animals. By his 

 corrections of Galen, Vesal was drawn into a violent con- 

 troversy with his master Sylvius, an energetic defender of 

 Galen's authority, and with his renowned contemporary 

 Eustachius, which did much for the development of Com- 

 parative Anatomy. At first animal anatomy was built up 

 only for the purpose of disclosing the cause of Galen's mis- 

 takes, but later through a zeal and love for facts. It is. 

 comprehensible that first of all vertebrates found con- 

 sideration, since they stand next to man in structure and 

 most of all challenge comparison. Thus there appeared in 

 the same century with Vesal's Human Anatomy drawings 

 of skeletions of vertebrates by the Nuremberg physician 

 Coiter; the anatomical writings of Fabricius ab Aquapen- 

 dente, and others. 



Beginning of Zootomy. But later attention was turned 

 also to insects and mollusks, indeed even to the marine 

 echinoderms, ccelenterates, and protozoa. Here, above all, 

 three men who lived at the end of the seventeenth century 

 deserve mention, the Italian Marcello Malpighi and the 

 Dutchmen Swammerdam and Leeuwenhoek. The former's 

 ' ' Dissertatio de bomycc " was the pioneer for insect anatomy, 

 since by the discovery of the vasa Malpighi, the heart, the 

 nervous system, the tracheae, etc., an extraordinary exten- 



