INFLUENCE OF NERYOUS SYSTEM. 391 



essential to a healthy course of nutrition, because in plants 

 and the early embryo, and in the lowest animals in which 

 no nervous system is developed, nutrition goes on without 

 it. But this is no proof that in animals which have a 

 nervous system, nutrition may be independent of it ; 

 rather, it may be assumed, that in ascending development 

 as one system after another is added or increased, so the 

 highest (and, highest of all, the nervous system) will 

 always be inserted and blended in a more and more inti- 

 mate relation with all the rest : according to the general 

 law, that the interdependence of parts augments with their 

 development. 



The reasonableness of this assumption is proved by many 

 facts showing the influence of the nervous system on nutri- 

 tion, and by the most striking of these facts being observed 

 in the higher animals, and especially in man. The influ- 

 ence of the mind in the production, aggravation, and cure 

 of organic diseases is matter of daily observation, and a 

 sufficient proof of influence exercised on nutrition through 

 the nervous system. 



Independently of mental influence, injuries either to por- 

 tions of the nervous centres, or to individual nerves, are 

 frequently followed by defective nutrition of the parts 

 supplied by the injured nerves, or deriving their nervous 

 influence from the damaged portions of the nervous centres. 

 Thus, lesions of the spinal cord are sometimes followed by 

 mortification of portions of the paralysed parts ; and this 

 may take place very quickly, as in a case by Sir B. C. 

 Brodie, in which the ancle sloughed within twenty- four 

 hours after an injury of the spine. After such lesions 

 also, the repair of injuries in the paralysed parts may take 

 place less completely than in others ; so, Mr. Travers men- 

 tions a case in which paraplegia -was produced by fracture 

 of the lumbar vertebrae, and, in the same accident, the 

 humerus and tibia were fractured. The former in due 

 time united ; the latter did not. The same fact was illus- 



