Stoweil.] 1^4: [July 25^ 



ments supply the muscular substance and the mucous membranes of 

 organs ; its development in relation with the development of, notably, the 

 heart and adjacent blood-vessels, and the stomach, renders its distribu- 

 tion somewhat asymmetrical, necessitating special anatomical study of its 

 dextral and sinistral relations, and giving corresponding and distinctive 

 physiological and pathological characters ; the relation of this nerve to 

 organic life, to the automatic and the reflex phenomena of respiration, 

 and to the so-called "inhibitory phenomena" gives importance to its 

 study. 



'Special anatomical characters: N. vagus and its rami are dis- 

 tributed to the most important viscera, at least to viscera most intimately 

 related to the functions of organic life, e. g., digestive — pharynx, oesopha- 

 gus, stomach, liver, pancreas, intestines ; circulatory — heart, pulmonary 

 arteries, pulmonary veins, systemic arteries and veins in the region of the 

 heart ; respiratory — larynx, trachea, bronchi, substance of lung. 



Special physiological characters : N. vagus is a sensory-motor 

 nerve, having both sensitive and motor fibres ; it controls, regulates or 

 modifies the movements and the secretory functions of the organs to 

 which it is distributed, and upon it depend the sensory phenomena which 

 characterize the respective organs. 



DESCRIPTION : Origin and cervical portion— N. vagus in 

 the cat {Fells domestica) takes its superficial origin from two regions of 

 the medulla : by 12-14 filaments from the ventral border of corpus resti- 

 forme and the depression line between cp. restiforme and the portion of 

 medulla next laterad (Fig. 3, 4),* in a line caudad of (posterior to) 

 the origin-filaments of N. glosso-pharyngeus (ninth pair of cranial 

 nerves), (Fig. 2, 4), from which nerve it is sometimes separated by a 

 small arterial twig of A. cerebellosa inferior ; and by 4-6 filaments imme- 

 diately ventrad in the slight depression line ventrad of oliva and cepha- 

 lad of the origin-filaments of the spinal portion of N. accessorius (Fig. 2. 

 L). The dorsal filaments form a somew'hat curved line of superficial 

 origin, measuring 3-4 mm. in caudo-cephalic direction, and presenting its 

 convexity dorsad (Fig. 2. X) '; the cephalic filaments are most ventral and 

 leave the medulla oblongata just caudad of A. cerebellosa inferior — a con- 

 siderable branch of A. basilaris at right angles with the main trunk and 



* Tliere is some difficulty in establishing satisfactorily the homologies of the 

 medulla. There are reasons for i-egarding the third nerve tract Ironi the dor- 

 simeson as the homologue of corpus olivarium ; this is manifestly not the cp. 

 olivarium of Foster as given in his " Practical rhysiology ;" it shonld he noticed 

 that the cephalic origin-filaments ot N. accessorius become apparent in this 

 depression line, while the caudal oiigin-tilaments apiieai- along the depression 

 line ventrad of this tract. The elliptical area (Fig. 1, ;{) laterad of ventripyra- 

 mis (anterior pyramid) and the one still dorso-lateral have relations iipon which 

 homologies might be based, giving each one the name oliva (corpus olivarium). 

 It is not proper in this connection to discuss homologies. I have made this 

 allusion in apology for the indeflnitencss of description of the origin-line of N. 

 vagus. Whatever homologies may be established and names assigned, the 

 figures (Fig. 3, 4) designate the relation. 



