20 ALIMENTATION. 



were escaping through, the opening. She would then say 

 that she felt better, but was still hungry. Prof. Busch infers 

 that hunger is composed of two separate sensations one 

 general, the other local ; the former resulting from the want 

 of material to supply the waste of tissue." 3 



These facts render it certain that the appetite and the sense 

 of hunger are expressions of a general want on the part of 

 the system, referred by our sensations to the stomach, but 

 really located in the general system. This want can only 

 be completely satisfied by the absorption of digested ali- 

 mentary matter by the blood and its assimilation by the 

 tissues. This is so evident, with our present knowledge, 

 that it is unnecessary to discuss the various theories which 

 have been proposed to account for the sense of hunger ; 

 such as repletion of the tubes of the stomach with gastric 

 juice, the reflux of bile from the duodenum, rubbing together 

 of the walls of the stomach, etc., etc. 



The sense of hunger is undoubtedly appreciated by the 

 cerebrum, and it has been a question whether there be any 

 special nerves which have the function of conveying this 

 impression to the great nervous centre. The nerve which 

 would naturally be suspected to possess this function is the 

 pneumo-gastric ; but in spite of certain observations to the 

 contrary, it has been proven that section of both of these 

 nerves by no means abolishes the desire for food. 2 Longet 

 has observed that dogs eat, apparently with satisfaction, after 

 section of the glosso-pharyngeal and lingual nerves. 3 The 

 last-named observer is of the opinion that the sensation of 

 hunger is conveyed to the brain through the sympathetic sys- 

 tem. Although there are various considerations which render 



1 BUSCH, Beitrag zur Physiolagie der Verdauungsorgane. YIRCHOW'S Arcfiiv, 

 1858, S. 140 etseq. A summary of this case is also given in the American Jour- 

 nal of the Medical Sciences, July, 1860, p. 217, and in the North American Med- 

 ico- Chirurgical Review of the same date. 



2 LEURET ET LASSAIGNE, Becker chcs Phyaiologiques et Chimiques pour servird 

 VHistoire de la Digestion, Paris, 1825, p. 211. 



8 LONGET, Traite de Physiologic, Paris, 1861, tome i., p. 20. 



