THE HISTORICAL DEVELOPMENT OF NEUROPHYSIOLOGY 



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FIG. j6. /,('//• th<" tliree ventricles of the brain as ens isaged by Albertus Magnus. Right: Leonardo 

 da Vinci's wax cast, the first CNperimental determination of their shape. 



them now, in the head; the passions he put in the 

 spinal marrow relating them to the heart, and the 

 lower appetites were given a place in the cord below 

 the diaphragm where they could play upon the liver. 

 For Plato these were the divisions of man's tripartite 

 soul. 



Under the influence of Galen the spinal nervous 

 system lost this position of importance, for according 

 to his doctrine other organs of the bod\', the liver and 

 the heart, were the primary sites for manufacture and 

 transmutation of the spirits. From the Islamic physi- 

 cians came the emphasis on three ventricles with 

 different functions, an anterior ventricle being the 

 receiver of all incoming spirits, a 'sensus communis,' 

 whereas a posterior ventricle formed the reservoir for 

 the outflow of animal spirits to all muscles through 

 their nerves. In a middle ventricle was to be found 

 man's rea.son. Similar ideas about triple cavities in 

 the brain and their allotted functions were generally 

 accepted throughout the imenlightencd middle ages 

 until finally an anatomist, no less a man than Leo- 

 nardo da Vinci (233), mapped the true shape of the 

 ventricles by pouring into them melted wax to form 

 a cast. 



Throughout the sixteenth and seventeenth cen- 

 turies, the structure of the brain was being unfolded 

 by the anatomists but still without a parallel investi- 

 gation of function. It was the cranial nerves that 



■2;j3. DA Vinci, Leonardo (1452-1519). On Ike Human Body: 

 The Anatomical, Physiological, and Embryological Drawings of 

 Leonardo da Vinci, with translations, emmendations and a 

 biographical introduction by C. D. O'Malley and 

 J. B. deC. M. Saunders. New York: Schuman, 1952. 



yielded first and Galen's seven pairs-^ (accepted on 

 his authority for 1400 years) swelled to nine in the 

 seventeenth century. In 1660 Schneider (234) identi- 

 fied the olfactory pair and 2 years later Willis (235) 

 dis.sected the accessory nerve that bears his name. 

 Today's recognition of 1 2 pairs of cranial nerves dates 

 from the eighteenth century and the work of von 

 Soemmering (236), whose books are illustrated by 

 engravings rivalled only by those of Charles Bell, 

 von Soemmering wrote copiously on anatomy, illus- 

 trating some of his work by his own hand and some 

 by the drawings of his pupil Koeck. 



The role played by each pair of cranial nerves was 

 still in soine degree obscure, for some nerves appeared 

 to have more than one function, and Whytt (237) 

 was one of the earlv workers to obserx'e how complex 

 their action might be. He found that the optic nerve 



234. Schneider, Conrad Victor (1614-1680). Liber primus de 

 catarrhis. Wittenberg: Mevius & Schumacher, 1660. 



235. Willis, Thomas (1621-1675). ^^ Anima Brutorum. In: 

 Opera Omnia. Leyden : Huguetan, 1681. 



236. Soemmering, Samuel Thomas (1755-1830). /> basi en- 

 cephali ei originibus nervorum cranio egredientum. Gottingen: 

 Vandenhoeck, 1 778. 



237. Whytt, Robert (1714-1766). An essay on the vital and 

 other involuntary motions of animals. Edinburgh : Hamilton, 

 Balfour and Neill, 1751. 



^* According to Galen's numbering, the seven pairs of 

 cranial nerves were: /) optic; 2) oculomotor and abducens 

 taken together; 3) and 4) were both parts of what is now called 

 the trigeminal, j) facial together with the auditory; 5) the 

 glossopharyngeal, vagus and accessory nerves; 7) the hypo- 

 glossal. 



