TRIFACIAL, OR TRIGEMINAL NERVE. 643 



the fact that section of the sympathetic filaments is well known to modify the nutrition 

 of parts to which they are distributed, producing congestion, increase in temperature, and 

 other phenomena, it is rational to infer that the modifications in nutrition which follow 

 section of the fifth after it receives filaments from the sympathetic system, not occurring 

 when these sympathetic filaments escape division, are to be attributed to lesion of the 

 sympathetic, and not to the division of the sensory nerve itself. 



A farther explanation is demanded for the inflammatory results which follow division 

 of the sympathetic filaments joining the fifth, inasmuch as division of the sympathetic 

 alone in the neck produces simply exaggeration of the nutritive processes, as evidenced 

 chiefly by local increase in the animal temperature, and not the well-known phenomena 

 of inflammation. 



It has been remarked by Bernard, that the " alterations in nutrition appear more 

 promptly in animals that are enfeebled." Section of the small root of the fifth, which 

 is unavoidable when the nerve is divided within the cranial cavity, generally interferes so 

 much with mastication as to influence seriously the general nutrition ; and this might 

 modify the nutritive processes in delicate organs, like the eye, so as to induce those 

 changes which are called inflammatory. The following observation, communicated by 

 Dr. W. H. Mason, Professor of Physiology in the Medical Department of the University 

 of Buffalo, is very striking in this connection : 



The fifth pair of nerves was divided in a cat in the ordinary way. By feeding the 

 animal carefully with milk and finely-chopped meat, the nutrition was maintained at a 

 high standard, and no inflammation of the eye occurred for about four weeks. The sup- 

 ply of food was then diminished to about the quantity it would be able to take without 

 any special care, when the eye became inflamed, and perforation of the cornea and 

 destruction of the organ followed. The animal was kept for about five months; at the 

 end of which time, sensation upon the affected side, which had been gradually improving, 

 was completely restored. 



The explanation we have to offer of the consecutive inflammatory effects of section 

 of the fifth with its communicating sympathetic filaments is the following : By dividing 

 the sympathetic, the eye and the mucous membranes of the nose, mouth, and ear are 

 rendered hyperoemic, the temperature is probably raised, and the processes of nutrition 

 are exaggerated. This condition of the parts would seem to require a full supply of 

 nutritive material from the blood, in order to maintain the condition of exaggerated 

 nutrition ; but, when the blood is impoverished probably as the result of deficiency in 

 the introduction of nutritive matter, from paralysis of the muscles of mastication upon 

 one side the nutritive processes in these delicate parts are seriously modified, so as to 

 constitute inflammation. The observation just detailed is an argument in favor of this 

 view ; for here the inflammatory action seemed to be arrested when the action of the 

 paralyzed muscles was supplied by careful feeding. With this view, the disorders of 

 nutrition observed after division of the fifth may properly be referred to the sympathetic 

 system. 



Pathological facts in confirmation of experiments upon the fifth pair in the lower 

 animals are not wanting ; but it must be remembered that, in cases of paralysis of the 

 nerve in the human subject, it is not always possible to locate exactly the seat of the 

 lesion and to appreciate fully its extent, as can be done when the nerve is divided by 

 an operation. In studying these cases, it sometimes occurs that the phenomena, par- 

 ticularly those of modified nutrition, are more or less contradictory. 



In nearly all works upon physiology, we find references to cases of paralysis of 

 the fifth in the human subject. In a recent article by Dr. H. D. Noyes, Professor of 

 Ophthalmology in the Bellevue Hospital Medical College, two interesting cases are re- 

 ported, which we had an opportunity of examining during the progress of treatment. 

 In both of these cases there was inflammation of the eye. In one case, the tongue was 

 entirely insensible upon one side, but there was no impairment of the sense of taste. An 



