424 ANATOMY AND PHYSIOLOGY OF THE BRAIN. 



has, however, actually excised this nucleus without respira- 

 tion being at once arrested or interfered with, and finds, 

 moreover, that it has no power to arrest or reduce the 

 heart's action if the pneumogastric nerves have been 

 previously divided. He concludes from this that the so- 

 called vital point is not essential to life, and that the fatal 

 interference with respiration and circulation, resulting fron 

 a wound of this nucleus, is entirely dependent on the irri- 

 tation of adjacent parts. 



It results that the oblong medulla is the centre of respi- 

 ratory movement, and, accordingly, any serious injury of 

 this organ is instantly fatal, while the remainder of the 

 brain may be entirely removed, if done with proper pre- 

 cautions, without immediate cessation of vital processes. 



The process of deglutition, like that of respiration, is 

 dependent on the oblong medulla, as is proved by its 

 persistence after the brain proper and the cerebellum have 

 been removed, and by the inability to swallow after the 

 medulla has been disorganised in experiments. This com- 

 plex act is effected through the facial, hypoglossal, glosso- 

 pharyngeal, pneumogastric, and probably the spinal acces- 

 sory nerves acting on the jaws, cheeks, tongue, palate, 

 pharynx and gullet. The whole is a reflex act, and results 

 from the successive and regular action of the above nerves 

 on the different parts engaged. The nerves on the two 

 sides must also act in perfect unison, and all this seems 

 dependent on the peculiar and intimate connection of the 

 grey nuclei from which they originate. 



The olivary bodies, in the opinion of Van- der Kolk, 

 preside over the articulation of sound, and their partial or 

 complete destruction, in the human subject, leads to a 

 corresponding loss of the power of speech. The above 

 author instances a number of cases in which the patients 



