346 On the Cerebellum. [May, 



It appears to me that it is of much greater consequence to dis- 

 prove these statements, than to dispute about their origin. 1 shall, 

 therefore, in the first place, examine the statements relating to the 

 structure of the spinal marrow, and shall then produce some ob- 

 jections relative to the functions of the cerebellum as stated by 

 Willis and by Mr. A. Walker. 



It is said that the spinal marrow is composed of four longitudinal 

 divisions, two larger, anterior, which may be traced into the cere- 

 brum ; and two smaller, posterior, which may be traced into the 

 cerebellum. This statement is erroneous in two respects : 1. There 

 are not four divisions ; there exist only two fissures, one at the 

 anterior part of the spinal marrow, the other at the hinder part ; 

 but there are no lateral fissures. Such are the statements of Gall 

 and Spurzheim ; and my recent examinations have convinced me of 

 their truth. Gall and Spurzheim have shown that the spinal mass 

 of nerves is composed of a series of as many swellings as there are 

 hairs of nerves, and they have pointed out that the anterior fissure* 

 is less deep than the posterior, and that the posterior nerves are 

 more considerable than the anterior. It is, therefore, erroneous to 

 say that of the four divisions the anterior are larger, and the poste- 

 rior smaller. 



Mr A. Walker considers the anterior fasciculi as ascending, and 

 the two posterior as descending. Gall and Spurzheim have shown 

 that the brain and cerebellum cannot be considered as the continua- 

 tion of the spinal marrow, any more than the spinal marrow can 

 thai of the brain and cerebellum. There are examples of monstrous 

 foetuses having onlv the lower parts of the spinal marrow, and yet 

 the posterior and anterior (or, according to Mr. A. Walker, the 

 ascending and descending,) fasciculi have been found to exist. It 

 is, thereifore, evident, that they cannot be considered as descending 

 from the cerebellum. Gall and Spurzheim have also shown that 

 not only the cerebellum, but also the hinder parts of the brain, are 

 brouiiht in communication with posterior parts of the spinal mass of 

 nerves, and that only a small fasciculus of the hinder part of the 

 spinal mass of nerves belongs to the cerebellum. 



Tlie physiological statements of Mr. A. Walker are not more 

 accurate than his anatomical ones ; they are merely suppositions, and 

 at variance witli nature. The cerebellum he considers as the organ 

 of volition, because it is placed opposite to the face, which contains 

 the chief orj^sms of sense. The expression oppnslle as to function 

 has no specific meaning. It cannot indicate a counteraction ; if this 

 were the case, the ears, which are situated opposite to one another, 

 should act in opposition to each other. 



1 must repeat Mr. A. Walker's supposition in his own words : — 

 " From tlie peculiar vpposiiion whicli subsists between the situa- 

 tion of the face and cerebellum, we are entitled to expect a simitar 

 opposition in their functions. As the face, therefore, occupied by 



♦ Anat. et Pbvf. ^c. pi. ii. fig. fl. 



