LECTURE X. 



I 



THE SPINAL CORD AND THE COMMENCEMENT OF THE MEDULLA 



OBLONGATA. 



GENTLEMEN: In the spinal cord, fibres of widely different 

 physiological significance lie crowded closely together. Those 

 cells which we regard as central organs lie side by side with 

 peripheral structures. You will, therefore, easily understand 

 how extremely difficult it is to detect the consequences and 

 symptoms which follow a disease or injury of any one of these 

 components of the spinal cord. 



Nevertheless, careful observation, both at the bedside and 

 at the post-mortem table, has taught us much in this connec- 

 tion. A certain number of diseases aft'ect only certain regions 

 of the spinal cord, always confining themselves to particular 

 columns or groups of cells, and leave all other parts of the cord 

 intact, or at least invade them very slowly. The investigation 

 of such diseases is naturally of great importance, as affecting 

 the subject which we have now in hand. Then, too, injuries, 

 sections, and compressions of the cord, such as may arise from 

 spinal caries or tumors, often enable us to draw valuable con- 

 clusions. 



Much less important results have been obtained by physio- 

 logical experiments on animals than by pathology. The neces- 

 sary operations are comparable to pathological processes of a 

 rather gross character, and in animals we know very little of 

 the nature arid source of the severed fibres, for the reason that 

 their cord has not been so thoroughly investigated as in the case 

 of human beings. 



It is, of course, beyond the pale of these lectures to give 

 even a short summary of the valuable discoveries which we owe 

 to pathological research. A number of excellent works will 

 afford you an easy introduction into this part of our subject. 



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