no COMPARATIVE PHYSIOLOGY OF THE BRAIN 



duced much higher up, at a certain point of the 

 medulla oblongata near the place where the vagus 

 enters, which Flourens called the nceud vital. This 

 place is supposed to be the respiratory centre. This 

 view is justified by two facts : first, the destruction of 

 the noeud vital causes a cessation of respiration ; 

 and, second, severing the spinal cord between the 

 nceud vital and the origin of the phrenic nerve like- 

 wise causes respiration to cease. These facts do 

 not justify the conclusion that Le Gallois, Flourens, 

 and with him the majority of modern physiologists, 

 have drawn -- namely, that the automatic activity of 

 respiration is located not in the segmental ganglia, but 

 higher up in the nceud vital. We should have just as 

 much right to assume that in Limulus the rhythmical 

 respiratory activity was produced higher up, in the 

 subcesophageal ganglion for instance, for in this animal, 

 too, respiration ceases for a time immediately after the 

 removal of the subcesophageal ganglion. We have 

 seen in this case, however, that the cessation is only 

 temporary, and is due to the shock, for respiratory 

 activity can go on again even when the whole central 

 nervous system, with the exception of the abdominal 

 ganglia, has been removed. Neither is the cessation 

 of respiration in Vertebrates permanent after removal 

 of the nceud vital or division of the spinal cord be- 

 tween the nceud vital and the third cervical vertebra. 

 Langendorff has made the important discovery that 

 decapitated Vertebrates which have lost the nceud 

 vital are still able to perform independent respiratory 



