THE SPINAL CORD AND CEREBELLUM 119 



tion that the former is inconceivable in the normal 

 state without the latter, and we know very well that 

 the presence and pressure of food in the intestine leads 

 not directly but indirectly — that is to say, through 

 the medium of sensation to the contraction which 

 follows. The latter is evidently of a reflex nature. 

 In view, however, of the involuntary character of intes- 

 tinal action, it seems natural to connect the nervous 

 mechanism of the causative or sensory impulses — 

 at least, when functioning normally — primarily with 

 the gray matter of the cord, though a secondary 

 connection may exist between the latter and the cere- 

 bellum. 



With respect to the functions of those fibres which, Puno- 

 instead of forming part of the posterior column for correspon- 

 any considerable distance, become almost immediately efemeuts 

 connected with the cells of the posterior horn of the J^^g ^'^° 

 gray matter, we are again reduced to conjecture. 

 Were one to look in this locality for cells correspond- 

 ing from a sensory point of view to well-nigh each 

 particular kind of cell to be found in the ventral or 

 motor-horn, we should expect the presence of musculo- 

 sensory cells to the skeletal muscles, which we should 

 be inclined to connect with thick or medium- sized 

 fibres rather than with the very fine fibres distributed 

 to this locality ; we should, in addition, expect similar 

 cells to be present to supply sensory impulses by which 

 the motor activity of the intestines is brought about, 

 and by which over and above this general movement 

 that of the mucous membrane is caused in the process 



