90 THIRD REPORT 1833. 



most important of the nerves, classed by Sir Charles Bell himself 

 as respiratory, — the phrenic and the external respiratory. These 

 two nerves branch from the cervical or regular double-rooted 

 series. Moreover, the circumstance of rising in linear suc- 

 cession is not found to associate nei'ves in function. " Be- 

 tween the roots of the phrenic nerve and those of the inter- 

 costals, there intervene in the same series the origins of the 

 three lowest cervical nerves, and the first dorsal, which go 

 chiefly to the axillary plexus and to the arm, and which are 

 not respiratory nerves." 



In recapitulation, the following facts are among the most 

 important that have been fully ascertained in the physiology of 

 the nervous system. 



1. One universal type has been followed in the formation of 

 the nervous system in vertebrated animals. The brain of the 

 human foetus is gradually evolved in the successive months of 

 uterine existence ; and these stages of progressive develop- 

 ment strictly correspond with permanent states of the adult 

 brain at inferior degrees of the animal scale. 



2. These successive increments of cerebral matter are found 

 to be accompanied by parallel advances in the manifestation of 

 the higher instincts and of the mental faculties. 



o. That the brain is the material organ of all intellectual 

 states and operations, is proved by observation on comparative 

 development, as well as by experiments on living animals, and 

 by the study of human pathology. But there does not exist 

 any conclusive evidence for I'eferring separate faculties, or 

 moral affections, to distinct portions of brain. 



4. Certain irregular movements are produced by injuries of 

 the corpora striata, thalami optici, crura cerebelli, and semi- 

 circular canals of the internal ear. 



5. The tubercula quadrigemina preside over the motions 

 of the iris, and their integrity seems essential even to the func- 

 tions of the retina. They are also, according to Flourens, the 

 points, at which irritation first begins to excite pain and mus- 

 cular contractions. 



6. The cerebellum appears to exercise some degree of con- 

 trol over the instruments of locomotion ; but the precise na- 

 ture and amount of this influence cannot be distinctly defined. 



7. The cerebrum, cerebellum and medulla oblongata possess 

 the faculty of acting primordially, or spontaneously, without 

 requiring foreign excitation. The spinal cord and the nerves 

 are not endowed with spontaneity of action, and are therefore 

 termed subordinate parts. 



