512 NUTRITION. 



a rabbit the fifth nerve is divided in the skull the loss of sensation in those 

 parts of the face of which it is the sensory nerve is followed by nutritive 

 changes. Very soon, within twenty-four hours, the cornea becomes cloudy : 

 and this is the precursor of an inflammation which may involve the whole 

 eye and end in its total disorganization. At the same time the nasal cham- 

 bers of the side operated on are inflamed, and very frequently ulcers make 

 their appearance on the lips and gums. And similar results have been seen 

 in other animals, including man. If the operation be conducted in a young 

 animal, which subsequently lives to maturity, the head may become bilater- 

 ally unsym metrical, as shown especially by the skull. Again, division of 

 both vagus nerves is very apt to be followed by inflammation of both lungs, 

 by fatty degeneration of the heart, and so by death. 



In several of these instances the effect is a mixed one, and the problem 

 complicated. Thus, in the case of division of the fifth nerve, seeing how 

 delicate a structure the eye is, and how carefully it is protected by the mech- 

 anisms of the eyelids and tears, it seems reasonable to suppose that the in- 

 flammation in question might simply be the result of the irritation caused 

 by dust and contact with foreign bodies, to which the eye, no longer guided 

 and protected by sensations, these being destroyed by the section of the nerve, 

 became subject. In the same way the ulcers on the lips and gums might be 

 explained as injuries inflicted by the teeth on those structures in their insen- 

 sitive condition. And some observers maintain that the inflammation of the 

 eye may be greatly lessened or altogether prevented if the organ be carefully 

 covered up, and in all possible ways protected from the irritating influences 

 of foreign bodies. Other observers, however, have failed to prevent the 

 inflammation in spite of every care. So, also the inflammation of the lungs 

 following upon division of both vagus nerves seems to be due, not to any 

 direct nutritive action of the pulmonary branches of the vagus on the pul- 

 monary tissue, but to food accumulating in the pharynx, owing to the paral- 

 ysis of the oesophagus and larynx, and then passing into the air passages, 

 and so setting up inflammation. Death in these cases is, moreover, often the 

 simple result of inanition caused by the paralysis of the oesophagus 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 discussing. 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 bedsores of cerebral apoplexy; some at 

 least of the cases of vesical affections attendant on spinal 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 sec- 

 tion of nerves ; the occurrence of certain eruptions, such as lichen, zona, 

 ecthyma, etc., in various spinal or cerebral diseases, and indeed the general 

 phenomena, and especially the topography of the eruption, of a large number 

 of cutaneous diseases. Lastly, but not least, we might quote the general 

 process of inflammation. These are examples of disordered nutrition. 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 



