I40 THE SPINAL CORD AND CEREBELLUM 



extended meaning than it usually possesses. If we 

 do not, how are we to explain the malnutrition and 

 the loss of muscular power and tone which in a 

 more or less pronounced form are fairly constant 

 and sometimes very marked symptoms after extirpa- 

 tion has taken place ? Let us but look at the cere- 

 bellum as an organ, the primary function of which is 

 to increase impulses of all sorts, but especially those 

 in which chemical action is intense, and all our diffi- 

 culties will fade away and vanish. Little by little we 

 shall be able to evolve a conception of that organ in 

 which the co-ordinating, the equilibrium controlling, 

 and the nutritive aspect of its functions will entirely 

 harmonize with one another ; we shall, indeed, see 

 that these various factors are absolutely essential a,nd 

 complementary. We have but to bear in mind a few 

 very simple truths : firstly, that no marked increase 

 of impulse can occur without an increase in the 

 chemical constituents out of which it is generated; 

 that is to say, you cannot obtain increased nervous 

 action, and, above all, prolonged nervous action, 

 without an increase in the blood-supply to the parts 

 affected ; secondly, that every increase of impulse 

 implies directly or indirectly an increase of chemical 

 action ; and, thirdly, that all voluntary action implies 

 an increase of impulse, for, as we have already shown, 

 an effect of will is but the result of the cerebellar and 

 other ' increase of impulse ' cells acting in combination 

 with the sensory or sensory and motor cells of the 

 cerebral cortex. Since, moreover, maintaining one's 



