4:06 NEJRVOUS SYSTEM. 



ralysis of motion, either on one side or the other, though the 

 animals operated upon were not able to stand. 1 



The action of the medulla as a reflex nerve-centre depends 

 upon its gray matter. "When this gray substance is de- 

 stroyed, certain of the important reflex functions are in- 

 stantly abolished. From its connections with various of the 

 cranial nerves, we should expect it to play an important part 

 in the movements of the face, in deglutition, in the action of 

 the heart and of various glands, etc., important points which 

 will be fully considered in their appropriate place. Its 

 most striking function, however, is in connection with respi- 

 ration. 



Connection of the Medulla Oblongata with Respiration. 

 It did not escape the observation of Galen, that when a 

 section was made at the summit of the spinal cord, the ani- 

 mal was suddenly destroyed. 2 This fact has been considered 

 as well established, since the time of Galen, but in 1809, Le- 

 gallois made a number of experiments upon rabbits, cats, 

 etc., in which he showed that respiration depends exclu- 

 sively upon the medulla oblongata and not upon the brain, 

 and he further located the part which presides over this 

 function at the site of origin of the pncumogastric nerves : 3 

 " For, if we open the cranium of a young rabbit, and ex- 

 tract the brain, by successive portions, from before back- 

 ward, cutting it by slices, we can remove in this way all of 

 the brain proper, and then the entire cerebellum and a part 

 of the medulla oblongata. But it (respiration) ceases sud- 

 denly when we include in a section the origin of the eighth 

 pair of nerves (pneumogastrics)." The experiments of Le- 

 gallois were repeated and confirmed before a commission 

 from the French Institute, composed of Yon Humboldt, 



1 VULPIAN, Systeme ncrveux, Paris, 1866, p. 495 



2 GALENUS, De Anatomicis Admtnistrationibus, Liber viii., Cap. ix. Opera, 

 Lipsiae, 1821, tomus ii., pp. 696, 697. 



3 LEGALLOIS, Experiences sur h prindpe de la vie. (Euvres, Paris, 1824, tome 

 i., p. 64. The date of these experiments is given by Legullois on page 74. 



