x THE FOBE-BRAIN 619 



higher psychical functions, which develop later, even in the phylo- 

 genetic series. 



We must now see if this finds much or little support from the 

 physiologist and the clinician. Of course there is no question of 

 discriminating any functional difference in the various areas of the 

 cortex which mature at different periods of foetal development 

 and make up the so-called association centres ; we are still far from 

 this even after Brodmanr's careful work on the structure of the 

 different parts of the cerebral cortex. It is only the psycho- 

 physiological importance of the association areas as a whole that 

 can be briefly indicated. 



It has often been assumed, from Gall to the latest observers, 

 that the frontal lobes, or at least their non-excitable or pre -frontal 

 portions, which attain a much higher development in man than 

 in the lower vertebrates, are the special seat of the intellectual 

 faculties. Leaving aside theoretical preconceptions and hypotheses, 

 no one who has been long occupied with the effects of partial 

 destruction of the brain in dogs or monkeys can fail to note the 

 insignificance and brief duration of the symptoms presented by 

 animals after removal of the pre-frontal lobes. Neither from 

 Munk's experiments nor our own, nor from those of Horsley and 

 Scha'fer, does it appear that after destruction of the pre-frontal 

 lobes the dog and the ape differ in any obvious way from intact 

 animals, in regard to their intelligence. 



The alterations of character described by Goltz in animals 

 after removal of the front half of both hemispheres are very 

 striking: they lose the power of inhibiting their reflexes, they 

 become abnormally restless and uneasy, and though formerly 

 docile and affectionate, become intractable and ill-tempered. But 

 it is evident that most of these psychical changes are due to 

 destruction of the sensory -motor area, and that little can lie 

 referred to the destruction of the pre-frontal region. 



L. Bianchi, following on Hitzig and Wundt, maintained that 

 the frontal lobe is " the organ for the physiological fusion of all 

 the sensory and motor products elaborated in other regions of the 

 cortex the organ of conscious synthesis of the main factors of 

 mental life the region in which are stored the greatest available 

 number of memory images, upon which the whole of the psychical 

 personality depends." 



Physiological experiment, however, shows clearly that the 

 functions thus attributed to the pre-frontal lobe are not real. The 

 monkey deprived of pre-frontal lobes, which Bianchi showed at the 

 International Congress of Medicine in Rome, 1894, manifested no 

 perceptible mental alteration, in the opinion of the Committee 

 appointed to examine it. Horsley and Scha'fer frequently noted 

 that the pre-frontal region may be removed without producing any 

 obvious symptom. 



