PSYCHIC FUNCTIONS OF THE CEREBRUM. 775 



degree in which the hemispheres are removed, all of the functions of the brain 

 are. impaired. If the latter is entirely eliminated, all of the faculties are lost. 

 Therefore, neither the different functions nor the different impressions are localized 

 in special situations. Goltz agrees with Flourens in the view that an uninjured 

 remnant of the same kind of cerebral tissue is capable to a certain degree of assum- 

 ing the functions of a destroyed portion. This capability on the part of portions 

 of the brain to act vicariously for portions that have been lost is designated by 

 Vulpian as "loi de suppleance" law of functional substitution. 



As opposed to the opinion of Flourens the phrenological teachings of Goll (died 

 1828) may be recalled. According to this observer the various mental functions 

 are localized in definite situations in the brain. A conspicuous faculty always 

 corresponds with a voluminous development of the respective portion of the cere- 

 bral cortex, which may even be recognized externally from the configuration of 

 the skull cranioscopy. Thus, the different mental functions are to be referred 

 to certain portions of the cerebral cortex. Spurzheim, who elaborated the system 

 of his friend, set up the following categories: The first class comprises the sensa- 

 tions, including the instincts and the feelings. The second comprises the faculty 

 of comprehension, including the power of recognition and that of thought. Al- 

 though the detailed application of this system exhibits a certain inflexibility, 

 obvious deficiencies and undeniable error, nevertheless the question is worthy of 

 serious consideration whether the fundamental thought of the system is entirely 

 to be rejected. The discovery of the localization of movements under the control 

 of the will and of conscious impressions and their association in the cerebrum 

 justify renewed examination of the phrenological system, although in quite another 

 manner than that pursued by the originator. 



After removal of both cerebral hemispheres in animals all voluntary 

 and consciously performed movement ceases, as well as every conscious 

 sensation and sensory impression. On the other hand the entire mechan- 

 ism, the harmony and the equilibrium of the movements persist, as well 

 as those functions that, independent of the memory, have been desig- 

 nated as lower or instinctive. The latter functions are localized in the 

 midbrain and are controlled through important reflex paths. 



Sudden arrest of the circulation in the brain, for example through decapita- 

 tion, is attended with immediate cessation of the mental processes. On permitting 

 arterial blood from a living horse to pass immediately through the carotids of the 

 decapitated head of a dog, Hayem and Barrier observed signs of maintained corv 

 sciousness and of volition in the head for more than ten seconds, but not later. 



The midbrain is connected not only with the gray matter of the 

 spinal cord and the medulla oblongata, the seat of the most extensive 

 coordinated reflexes, but it contains also sensory elements, as well as 

 fibers, derived from the higher sense-organs, which may likewise have a 

 reflex effect upon motility. Finally, the midbrain contains inhibitory 

 apparatus for reflexes. The associated action of all of these parts makes 

 the midbrain a controlling organ for the harmonious execution of move- 

 ments, and in a higher degree than the medulla oblongata. This is seen 

 especially from the fact that animals with the midbrain preserved are 

 capable under varied conditions of maintaining the equilibrium of their 

 body, which is lost at once if the midbrain is destroyed. Christiani 

 determined the situation of the coordinating center for locomotion 

 and the maintenance of equilibrium in mammals to be in front of the 

 inspiratory center of the third ventricle. 



The significance of the cooperation between cutaneous sensibility and sense- 

 impressions for the maintenance of equilibrium will be made clear from the 

 following considerations: The frog deprived of its brain at once loses its power 

 of equilibration as soon as the skin is removed from the hind legs. The influence 

 of visual impressions is recognized from the inability to maintain the equilibrium 

 that is observed in connection with nystagmus, and from the vertigo that often 



