650 INFLUENCE OF NERVES ON NUTRITION. [Book ti. 



simple result of inanition caused by the paralysis of the oesoph- 

 agus allowing no food to reach the stomach. The phenomena 

 of the paralytic secretion of saliva are also of a complicated 

 nature. 



But even without insisting on such instances as the above, 

 various other phenomena of disease seem to indicate such an 

 influence of the nervous system on nutrition as we are discuss- 

 ing. As examples we might mention the rapid and peculiar 

 degeneration of and loss of contractility in the skeletal muscles 

 in certain affections of the spinal cord, the changes in the 

 muscles being more rapid and profound than in the nerves ; the 

 phenomena of bed-sores, especially the so-called acute bed-sores 

 of cerebral apoplexy; some at least of the cases of vesical affec- 

 tions attendant on spinal or cerebral diseases or injuries ; the 

 more rapid atrophy and loss of contractility in muscles which 

 follow upon contusions of nerves as compared with the effects 

 of simple section of nerves ; the occurrence of certain eruptions, 

 such as lichen, zona, ecthyma, &c, in various spinal or cerebral 

 diseases, and indeed the general phenemona, and especially the 

 topography of the eruption, of a large number of cutaneous 

 diseases. Lastly but not least we might quote the general pro- 

 cess of inflammation. These are examples of disordered nutri- 

 tion. To them we might add as instances of altered but yet 

 orderly nutrition the remarkable connections observed between 

 changes in the form of the fingers and growth of the nails and 

 hairs, and certain internal maladies, such for instance as the 

 ' clubbed fingers ' of phthisical and other patients, and the like. 

 We might also call attention to the influence of light on the 

 nutrition of animals. The experience of blind people and blind 

 animals indicates some special connection between visual sensa- 

 tions and the nutrition of the skin; and this can hardly be other 

 than a nervous connection. The effects of prolonged darkness 

 on nutrition in general and the experimental results which shew 

 that the total metabolism of the body is influenced by light, 

 also suggest some nervous action. The influence of cold again 

 in determining the growth of hair points in the same direction. 



Making every allowance for the intervention as factors in 

 the production of the phenomena quoted above of such common 

 actions of the nervous system as are already well known to us, 

 such as vaso-motor changes, making every allowance for the 

 consequences of the failure or bluntness of sensation and the 

 absence of those beneficial after results of muscular activity 

 which we pointed out in § 81, recognizing moreover that changes 

 in one organ may affect the condition of other distant organs 

 by changes induced in the composition or qualities of the blood, 

 there still remains a residue which seems distinctly to point to 

 the conclusion that the influence of the nervous system is not 

 limited to such changes of the muscles as belong to the produc- 



