NERVOUS SYSTEM AND HEREDITY 209 



metrical that it is impossible to attribute them solely 

 to external injuries. They occur only during the first 

 weeks after the operation, disappearing later on (5). 

 It is conceivable that the cause of these phenomena is 

 to be sought in abnormal chemical processes which 

 are perhaps caused by the vasomotor nerves in so far 

 as disturbances in the supply of oxygen, etc., are de- 

 termined by them. These disturbances occasionally 

 fail to appear. Physicians are familiar with these 

 phenomena of bed-sores which ensue after lesion of 

 the spinal cord. One fact that Goltz and Ewald found 

 is especially interesting for the theory of these pro- 

 cesses. When they severed the spinal cord of animals, 

 these phenomena of ulceration of the skin were very 

 pronounced. But if they afterward operated on the 

 spinal cord behind the cut, the disturbances were much 

 less severe or failed to appear. Thus the separation 

 of a part of the spinal cord from the brain is accom- 

 panied by more serious consequences than the sub- 

 sequent destruction of the spinal cord itself (5). 



An inflammation of the cornea occurs generally 

 after the division of the trigeminus of the same side. 

 This inflammation is naturally caused by bacteria, but 

 the fact that these bacteria affect the cornea whose 

 sensory nerve is severed might have two causes : 

 either the animal on account of the lack of sensibility 

 might not notice the foreign bodies (dust, etc.) that 

 get into the eye and cause a wound, or as a result of 

 the division of the nerve changes take place in the 

 cornea which render it more susceptible to inflam- 



