540 



PHYSIOLOGY 



CHAP. 



Prochaska accounts for the dreams of sleep on the supposition that 

 the organ of perception, which is dulled in sleep, is distinct and 

 perhaps remote from the organ of ideation. 



Bichat (1771-1802), on the contrary, returned partially to the 

 older view. Every kind of sensation has its centre in the hrain, 

 but the brain is never affected by the passions; the organs of 

 organic life and the sympathetic ganglia are the exclusive seat of 

 the latter. Lesions of the liver, stomach, spleen, intestines, heart, 



Fio. 273 a. External surface of brain. Representation of cortical areas according to the cyto- 

 architecture of the grey matter in man. (Brodmann.) In this and the next figure the 

 different areas are marked by numbers and various other signs. Such are area 4, distinguished 

 by large black dots, which is the giganto-pyramidal area (motor zone) ; and area 17, marked by 

 small black points, the area striata (visual zone). 



etc., produce a variety of affections which cease when the cause is 

 removed. Fear, for instance, arises from the stomach, choler from 

 the liver, goodness from the heart, joy from the intestines. ' 



Yet more astonishing is the theory put forward by the great 

 anatomist Sommering in 1796, which is to some extent a return 

 to the ideas of Herophilus and Galen, who localised the seat of the 

 pneuma psychikon in the cerebral ventricles. During his anatomical 

 studies on the real origin of the cranial nerves, he was struck by 

 the fact that nearly all terminated in the walls of the cerebral 



