4:12 NERVOUS SYSTEM. 



The pineal gland and the pituitary body, in their structure, 

 present a certain resemblance to the ductless glands, and their 

 anatomy has been considered in another volume. 1 Passing 

 over the purely theoretical views of Galen, "Willis, Descartes, 

 and other of the older writers, who had very indefinite ideas 

 of the functions of any of the encephalic ganglia, we have 

 only to say that the uses of the pineal gland and pituitary 

 body in the economy are entirely unknown. The same re- 

 mark applies to the corpus callosum, the septum lucidum, 

 the ventricles, hippocampi, and various other minor parts 

 that are necessarily described in anatomical works. It is 

 useless to discuss the early or even the recent speculations 

 with regard to the functions of these parts, which are entirely 

 unsupported by experimental or pathological facts, and which 

 have not advanced our positive knowledge. Most of the 

 parts just enumerated have no physiological history. 



Rolling and Turning Movements following Injury of Cer- 

 tain Parts of the Encephalon. 



The remarkable movements of rolling and turning, pro- 

 duced by section or injury of certain of the commissural 

 fibres of the encephalon, are not very important in their 

 bearing upon the functions of the brain, and are rather to be 

 classed among the curiosities of experimental physiology. 

 These movements follow unilateral lesions, and are depend- 

 ent, to a certain extent, upon a consequent inequality in 

 the power of the muscles on one side, without actual paraly- 

 sis. Yulpian enumerates the following parts, injury of 

 which, upon one side, in living animals, may determine 

 movements of rotation : 



" 1. Cerebral hemispheres ; 



" 2. Corpora striata ; 



" 3. Optic thalami (Flourens, Longet, Schiff) ; 



" 4. Cerebral peduncles (Longet) ; 



" 5. Pons Yarolii ; 



1 See vol. in., Ductless Glands, p. 364. 



