THE NERVOUS SYSTEM. 465 



combined, under this common name of nerves, the 

 tendons ; though he distinguished such nerves from 

 those which arise from the brain and the spinal 

 marrow, and which are subservient to the will. In 

 Galen's time this subject had been prosecuted more 

 into detail. That anatomist has left a Treatise ex- 

 pressly upon The Anatomy of the Nerves; in which 

 he describes the successive pairs of nerves : thus, 

 the first pair are the visual nerves : and we see, in 

 the language which Galen uses, the evidence of the 

 care and interest with which he had himself exa- 

 mined them. "These nerves," he says, "are not 

 resolved into many fibres, like all the other nerves, 

 when they reach the organs to which they belong ; 

 but spread out in a different and very remarkable 

 manner, which it is not easy to describe or to 

 believe, without actually seeing it." He then gives 

 a description of the retina. In like manner he 

 describes the second pair, which is distributed to 

 the muscles of the eyes ; the third and fourth, which 

 go to the tongue and palate; and so on to the 

 seventh pair. This division into seven pairs was 

 established by Marinus 2 , but Vesalius found it to be 

 incomplete. The examination which is the basis 

 of the anatomical enumeration of the nerves at 

 present recognized, was that of Willis. His book, 

 entitled Cerebri Anatome, cui accessit Nerwrum 

 descriptio et usus, appeared at London in 1664. He 

 made important additions to the knowledge of 



* Die. Sc. Med. xxxv. 467. 

 VOL. III. H H 



