XIII 



EESPIEATOEY EHYTHM 



445 



If this were correct, the respiratory hemiplegia consequent on 

 unilateral division of the lateral bundles in the upper cervical 

 region would disappear after a short time. It is, however, true 

 that with great care the whole of the so-called nceud vital of 

 Flourens, as also, according to Schiff, the whole internal or median 

 half of the ala cinerea can be destroyed, without producing 

 permanent arrest of respiration. It is only when the external 

 half of the ala cinerea is separated from the central grey matter 

 that respiration on the corresponding side is abolished for ever. 



FIG. 203. Section of spinal bulb in man at level of exit ot vagus and hypoglossal nerves from the 

 section. (Lueiana.) Crst Rectiform body ; Nfc, nucleus of funiculus cuneatus ; Villa, ascending 

 root of auditory nerve ; NX, nucleus of vagus, which appears as ala cinerea at surface of 

 rhomboidal sinus ; NXII, nucleus of hypoglossal ; Nm median nucleus (or nucleus of funi- 

 culus teres) ; IXa, ascending root of glosso-pharyngeal (or funiculus solitarius) ; Fr, formatio 

 reticularis ; R, raphe ; SgB, substantia gelatinosa Rolandi ; Va, ascending root of trigeminal ; 

 X, vagus ; Na, nucleus ambiguus ; Oae, accessory external olive ; Ooa, accessory anterior 

 olive; 0, olive ; XII, hypoglossal; L, fillet; Py, pyramidal bundle; Narc, arciform 

 nucleus 



From these facts (which were confirmed in the last years of his 

 life by Schiff, and by his pupil Girard) we must conclude that the 

 most indispensable part of the respiratory centre lies within the 

 outer half of the ala cinerea, bordering on the median limit of the 

 restiform body, i.e. external to the dorsal or sensory nucleus of 

 the vagus and glosso-pharyngeal, along with the solitary bundle, 

 and the dorsal and distal portion of the formatio reticularis 

 (Fig. 203). 



In the year 1873 Gierke, under Heidenhain's direction, 

 carried out a series of experiments with a view to determining 



