NERVE INJURIES 197 



pain is felt throughout its distribution. It is 

 an advantage to protect the nerve junctions from 

 invasion by fibrous tissue ; this may be done by 

 enclosing them in a ring or tube of superficial vein, 

 or in Cargile membrane. There is some doubt as to 

 whether the latter does any good. 



There is yet another method, which is sometimes 

 the only one available. Langley made some very 

 interesting experiments on the effects of joining up 

 the cut ends of different nerves, and found that their 

 functions could be transposed. Thus he turned the 

 cat's vagus into the cervical sympathetic, and allowed 

 regeneration to take place. The vagus is of course 

 the nerve of swallowing, and therefore, whenever 

 the cat lapped milk, all the effects of stimulation of 

 the cervical sympathetic were seen on the side 

 operated on — dilatation of the pupil, starting of the 

 eye, sweating, retraction of the nictitating membrane, 

 paUor of the ear, bristling of the hair, and quicken- 

 ing of the heart beat. When, however, the (purely 

 sensory) lingual nerve and the (purely motor) hypo- 

 glossal were crossed in like manner there was no 

 result. 



The method of nerve anastomosis was introduced 

 into practical surgery by Ballance, who put part of 

 the spinal accessory nerve into the peripheral end 

 of the degenerated facial nerve to relieve intractable 

 facial palsy. The result was excellent, but there was 

 a tendency of course for the face and the trapezius 

 to contract together, and smiling was accompanied 

 by jerking of the shoulder. To avoid this the hypo- 

 glossal is now utihzed instead of the spinal acces- 



