FUNCTIONS OF THE MEDULLA OBLOXGATA. 515 



reflected the nervous force necessary for the performance 

 of respiration and deglutition. It has been proved by 

 repeated experiments on the lower animals, especially by 

 those of Legallois, Flourens, and Longet, that the entire 

 brain may be gradually cut away in successive portions, 

 and yet life may continue for a considerable time, and the 

 respiratory movements be uninterrupted. Life may also 

 continue when the spinal cord is cut away in successive 

 portions from below upwards as high as the point of origin 

 of the phrenic nerve, or in animals without a diaphragm, 

 such as birds or reptiles, even as high as the medulla 

 oblongata. In Amphibia, these two experiments have 

 been combined : the brain being all removed from above, 

 and the cord from below ; and so long as the medulla 

 oblongata was intact, respiration and life were maintained. 

 But if, in any animal, the medulla oblongata is wounded, 

 particularly if it is wounded in its central part, opposite 

 the origin of the pneumogastric nerves, the respiratory 

 movements cease, and the animal dies as if asphyxiated. 

 And this effect ensues even when all parts of the nervous 

 system, except the medulla oblongata, are left intact. 



Injury and disease in men prove the same as these ex- 

 periments on animals. Numerous instances are recorded, 

 in which injury to the human medulla oblongata has 

 produced instantaneous death ; and, indeed, it is through 

 injury of it, or of the part of the cord connecting it with 

 the origin of the phrenic nerve, that death is commonly 

 produced in fractures and diseases with sudden displace- 

 ment of the upper cervical vertebrae. 



The centre whence the nervous force for the production 

 of combined respiratory movements appears to issue is in 

 the interior of that part of the medulla oblongata from 

 which the pneumogastric nerves arise ; for with care the 

 medulla oblongata may be divided to within a few lines of 

 this part, and its exterior may be removed without the 

 stoppage of respiration ; but it immediately ceases when 



