690 FUNCTIONS OF THE CEREBRUM [CH. XLVIII. 



in this way. No cortical centre is purely motor or purely sensory, and this one, 

 though usually called motor, has its sensory complement probably from the eyeballs 

 and eyelids (5th nerve). The newly developed grey matter between it and the 

 Rolandic region is an area probably concerned in the association of eye movements 

 with equilibration and the maintenance of the erect position ; we know that the 

 fibres from the frontal lobe to the cerebellum are very numerous. 



The auditory area is in the posterior part of the upper temporal 

 convolution, and is connected to the visual by annectent gyri. Taste 

 and smell are closely connected ; their cerebral area is in the uncinate 

 convolution and tip of the temporal lobe. This part is enlarged in 

 animals with a keen sense of smell. 



Munk's view, supported in this country by Bastian, Mott, and 

 numerous others, is that the sensory fibres from the skin and 

 muscles terminate in the Eolandic area; and the histological 

 researches of Golgi and Eamon y Cajal (see figs. 479 and 482) point 

 to the same conclusion. This is, in fact, what one would expect ; 

 volition and feeling are associated together so closely physiologically, 

 that anatomically we should expect to find the commencement of the 

 volitional fibres contiguous to the terminations of the sensory fibres. 

 That this is really the case has been shown by a careful examination 

 of the sensation in animals in which the Eolandic area has been 

 removed, and in cases of hemiplegia in man. A delicate test is to 

 place a clip on the fingers or toes, taking care the animal does not 

 see the clip put on. If there is loss of tactile sensibility the monkey 

 either takes no notice at all of the clip or removes it after a long 

 delay. Whereas if sensation is perfect the monkey at once seizes the 

 clip and flings it away. It is found that the intensity of both the 

 motor and sensory paralysis are directly proportional to each other. 

 Hence the term motor area, which we have been provisionally 

 employing for the Eolandic area, should be replaced by the more 

 correct term sensori-motor or kineesthetic area. These new terms 

 indicate that what really occurs in the Eolandic area is a sense of 

 movement, and this acts as a stimulus vid the pyramidal tracts to the 

 true motor centres which are in the opposite anterior horn of the 

 spinal cord. If the posterior roots of the spinal nerves are divided 

 there is a loss of sensation, and so the sense of movement cannot 

 reach the brain from the muscles, and consequently the muscles are 

 not called into action ; when all the posterior roots coming from a 

 limb in a monkey are cut, the muscles, so far as voluntary move- 

 ments are concerned, are in fact as effectually paralysed as if the 

 anterior roots of the spinal nerves had been cut. The muscles, 

 however, do not degenerate as they would if the anterior roots had 

 been cut. They merely undergo a small amount of wasting due to 

 want of use (" disuse atrophy "). 



Prof. Schafer is one prominent worker who has not accepted 

 views on this subject. He still regards the Eolandic area as 



