340 Dr. A. Waller on the Investigation of the L^ a Y 



glion the nervous elements retained all their normal structure, evidently 

 showing that continuity with the spinal cord does not prevent it from 

 becoming disorganized, whereas its connexion with the intervertebral gan- 

 glion suffices to preserve its integrity of structure. 



In the divided anterior root the phenomenon takes place in an exactly 

 inverse manner from the former. For in this instance the central portion 

 connected with the spinal cord retains its normal structure, while the distal 

 part becomes disorganized and reduced to a granular state. We therefore 

 arrive at this conclusion, viz. that the spinal cord confers on the anterior 

 root that unknown vital power whereby its elements resist granular disor- 

 ganization ; whereas for the posterior root, on the contrary, this preserva- 

 tive power is no longer an attribute of the spinal cord, but resides in the 

 ganglion. 



The author pointed out the important bearings these results had on pa- 

 thology — that henceforth in diseases of the spinal cord and of the brain, we 

 had to endeavour in our pathological examinations of these parts to ascer- 

 tain in each case how far the alterations could be referred to the separation 

 of a part from its trophic centre. 



Dr. Waller then referred to his researches on the Pneumogastric and 

 Spinal Accessory Nerves. 



If, from among the various nerves of the human body, we were called upon 

 to point out that which has most exercised the patience and ingenuity of 

 anatomists and physiologists, we should at once indicate the vagus. Its 

 distribution to the larynx, the lungs, the heart, and the stomach shows us 

 at a glance the important nature of its functions. At its origin it is formed 

 by roots springing from the medulla oblongata, to which is added after- 

 wards a considerable branch from the accessorius, which joins and mingles 

 with the pure vagus with which its fibres become intimately blended. The 

 problem to be solved, therefore, is the precise functions of each or of either 

 (?*. e. the accessorius or pure vagus) before their anastomosis. 



In ordinary circumstances nothing would be more simple than to uncover 

 the nerves and to galvanize each separately, as in the case of an ordinary 

 spinal pair. But here the case is different. In their origin these nerves 

 are so close to the medulla oblongata and the blood-vessels that any such 

 operation is quickly fatal, and the irritation of the minute roots of each 

 nerve in close proximity renders it impossible to obtain any precise results. 

 Professor BischofTs attempts at division of the roots of the accessorius in 

 the vertebral canal rendered it probable that it gave motor fibres to the 

 vagus which were distributed to the larynx. So far the previsions of Sir 

 Charles Bell were confirmed, who compared the internal branch to the an- 

 terior or motor part of a spinal pair, and the true vagus with its ganglion 

 to the posterior root. Professor C. Bernard had, however, succeeded in 

 entirely destroying the power of the accessorius by evulsion of its roots, 

 and had arrived at the conclusion that all the fibres of this nerve are distri- 

 buted to the laryngeal muscles whose functions are connected with the pro- 



