INVENTION OF THE MICROSCOPE 19 



that they were built upon the same plan as man. 1 Willis, of 

 Oxford and London, in his Cerebri A natoine (1659) recognised 

 the necessity for comparative study of the structure of the 

 brain. He found out that the brain of man is very like that 

 of other mammals, the brain of birds, on the contrary, like 

 that of fishes ! 2 He described the anatomy of the oyster 

 and the crayfish. He had, however, not much feeling for 

 morphology. 



The foundation of the Jardin des Plantes at Paris in 1626 

 and the subsequent addition to it of a Museum of Natural 

 History and a menagerie gave a great impulse to the study 

 of comparative anatomy by supplying a rich material for 

 dissection. Advantage was taken of these facilities, particu- 

 larly by Claude Perrault and Duverney. 3 In a volume 

 entitled De la Mecaniqne dcs Aniinanx, Perrault recognises 

 clearly the idea of unity of type, and even pushes it too far, 

 seeking to prove that in plants there exists an arterial system 

 and veins provided with valves. 4 



The beginning of the i/th century saw the invention of 

 the microscope, which was to have such an enormous in- 

 fluence upon the development of biological studies. It did 

 not come into scientific use until well on in the middle of the 

 century. Just before it came into use Francis Glisson (1597- 

 1677), an Englishman, gave in the introduction to his treatise 

 on the liver an account of the notions then current on the 

 structure of organic bodies. He classifies the parts as 

 "similar" and "organic," the former determined by their 

 material, the latter by the form which they assume. The 

 similar parts are divided into the sanguineous or" rich in 

 blood and the spermatic. Both sets are further subdivided 

 according to their physical characters, 5 the latter, for instance, 

 into the hard, soft, and tensile tissues. The classification 

 resembles greatly that propounded by Aristotle, though it is 

 notably inferior in the details of its working out. 



1 Zootomia democri/ea, Nuremberg, 1645 '> Antiperipatias, sen de 

 respiratione piscium, Amsterdam, i66r. ' Radl, loc. '/., i., p. 50. 



' Perrault et Duverney, Me moires pour servir a thistoire des Animaitx, 

 Paris, 1699. 



1 F. Houssay, Nature et Sciences naturelles, Paris, p. 76, n.d. 

 5 Foster, loc. a'/., p. 85. 



