NERVES. 245 



able, indeed, that the impression is conveyed to the liver 

 through the sympathetic system, for it has been shown by 

 Schiff and Longet, that animals do not become diabetic after 

 irritation of the floor of the fourth ventricle, when the 

 branches of the sympathetic going to the solar plexus have 

 been divided. 1 The operation, however, of dividing the 

 sympathetic nerves in this situation is so serious, that it may 

 interfere with the experiment in some other way than by 

 the direct influence of the nerves upon the liver. 



Influence of the Pneumogastrics upon the Stomach and 

 Intestines. The number of observations that have been 

 made upon the influence of the pneumogastric nerves on 

 digestion in the stomach is immense, and many of the earlier 

 experiments were quite contradictory. We do not propose, 

 however, to treat of this subject from a purely historical 

 point of view, for the reason that, before 1842 and 1843, 

 when gastric fistulas were first established in living animals, 

 by Bassow and Blondlot, little was known of the normal 

 movements of the stomach and of the mechanism of the 

 secretion of the gastric juice ; and farther, before the obser- 

 vations of Bouchardat and Sandras, in 1847, the effects of 

 section of the nerves in the neck upon the action of the 

 oesophagus in deglutition were not understood. If we study 

 the literature of the subject anterior to 1842, we find a great 

 deal of confusion, due to the facts just stated. Longet, in his 

 work on the nervous system, published in 1S42, gives an 

 excellent account of the various experiments up to that date. 

 He cites a great number of authors, Bichat, Tiedemann and 

 Gmelin, Bischoff, Schultz, Breschct and Milne Edwards, 

 Magendie, Miiller, Mayo, and many others, to whom we will 

 not refer in detail. 2 Leaving out of the question, then, most 

 of the earlier experiments, we shall treat of the influence of 



1 LOXGET, Traite de physiologie, Paris, 1869, tome Hi., p. 553. 

 * LOXGET, Anatomie et physiologie du systeme nerveux, Paris, 1842, tome iL, 

 p. 320, et seq. 



