ABDOMEN. 269 



of attempting to teach the physiology of reflexes, but simply to impress on the 

 student the imperative necessity of being able, in dissection, to show the place 

 where somatic and sympathetic nerves communicate, by the ncrvi comniunicantes. 



Is there any difference in the traiismissional power of souiatie and sn/ipathetic 

 nerves / 



From the decided difference in the character of pain reported by these two 

 nerves we would conclude there is a difference. 



Wliat is the difference in tran smissional power / 



This is conjectural only. Simply to aid the memory, we might view the 

 subject in the light of logical reasoning. For physiological facts, however, you 

 must consult physiologists. Structure is the correlative of function ; hence, 

 m.irked differences in function entail consequent marked differences in structure. 



Renal Plexus 



y ntdney - 



Renal Colic 



X &reter. Bladder, Lumbar and Penis reflex ar*>. 



Cardiac Plexus 



X -X Heart 



-X Arm, Finyers, Shoulder and Abdominal Wall* 



Cardiac Plexus L 



n y 



-X- 



Pneumonia 



1 Pain in Lumbar ret/ton 



2 Pain in the Kpigasfrum 

 .? Pain on the sound side 



Pelvic Plexus ^^- Ovaritis 



x <C^ Salpinailts 



Back ^~^^Displacements 



X Chest 



Extremities - Tfie reflex areas frequently 



(iastric Plexus 

 x y Stomach 



nd Cancer 

 X Abdominal Walls, TTie reflex area 



ffypogastric Plexus 



y ffites tine - 



Enterataia 



'liacreyion end Umbilicus , The. reflex area 



FIG. 186. SHOWING SCHEMATICALLY A SENSORY REFLEX CIRCUIT. 



The converse is true. The sympathetic individual fibre is smaller ; its fibres 

 undergo numerous interruptions, not only in the ganglia of the gangliated cord, 

 but also in numerous other plexuses, of which the plexuses of Auerbach and 

 Meissner may be taken as the type. 



Somatic and sympathetic nerves are routes by which nerve-impressions travel. 

 Nerve-impulses, of whatever kind, are, then, projectiles, and amenable to the law 

 of projectiles : " Projectiles follow the line of greatest traction, the point of 

 least resistance, or the resultant of the two." If, then, the small calibre of 

 sympathetic nerves, and their frequent interruptions, form a resistance to nerve- 

 impulses, then somatic nerves, possessing neither of these assumed impedi- 

 ments, logically furnish lines of least resistance. 



Our conclusion would be, then, that in the case of a given irritation in a sym- 

 pathetic area, as in cardiac valvular lesion, the sympathetic reports the pain to 



