THE INNERVATION OF THE LUNGS. 457 



respiratory movements/' . . . "One cranial nerve, as we 

 shall see, is especially concerned in respiration, viz.: the vagus 

 nerve; but if, after removal of the brain above the medulla, 

 both vagus nerves be divided, respiration still goes on; indeed, 

 the respiratory impulses proceeding from the center are, though 

 in a peculiar way, exaggerated." A feature of the experiments 

 referred to is that electricity is not in any way stated to have 

 been used; we are dealing, therefore, with positive facts, 

 which may be summed up in the statement that division of 

 the vagus does not arrest respiration. Such being the case, how 

 can the vagal center be considered as the respiratory center, 

 or as Flourens's no3ud vital? If removal or injury to the latter 

 suffice to arrest respiration, section of the vagi should do the 

 same. Since it does not, it seems obvious that the respiratory 

 center cannot be vagal, and that the "nceud vital" is not the 

 respiratory center. 



The role of the vagus in pulmonary functions becomes 

 clear, however, if we grant this nerve functions similar to those 

 we have found it to fulfill elsewhere: i.e., as companion to the 

 general motor nerves, and intended to incite and govern the ex- 

 acerbations of functional activity assumed when from "passive" 

 the organ's work becomes "active," and to transmit to the bulb 

 the impulses that bring on the counter-impulses which main- 

 tain and regulate temporarily and in lieu of its mate, the 

 general motor supply these exacerbations of activity. It 

 might well be severed under these circumstances without ar- 

 resting respiration. The general motor fibers would merely 

 continue their work, though "in a peculiar, exaggerated" way. 



If the vagal center is not that which presides over res- 

 piration, to which portion of the bulb can we ascribe this im- 

 portant function. With our limited array of nervous systems 

 to choose from,, we are led to consider the "general motor 

 center" in toto as a respiratory center. But a curious fact 

 appears when this question is closely studied: i.e., that what 

 has been called the "respiratory center" includes the parts of 

 the bulb which we consider as the "general motor center" and 

 "the vasomotor center," or rather the area to which the latter 

 term has been applied. 



"The portion of the medulla the removal of which exerts 



