338 LECTURE XIV. 



intersected by it. Still the whole of the territories be- 

 longing to the nerves which lie along the thread, are not 

 thrown into the same morbid condition, but the nutritive 

 irritation is limited to the immediate vicinity of the 

 thread. No surgeon expects in operations of the kind, 

 that all the nerve -territories traversed by the thread, 

 will become diseased in their whole extent. Great com- 

 plaints would have to be raised against nature, if every 

 ligature, every seton were to exercise an irritating influ- 

 ence, beyond the limits of the parts with which it is in 

 immediate contact, upon the whole extent of the nerve- 

 districts which it passes through. Thus we see in a tis- 

 sue in which what takes place in such a case can be very 

 clearly traced, namely in the cornea, that in parts of it 

 to which no vessels extend, there are certainly still nerves 

 which possess a reticular arrangement, and leave larger 

 and smaller districts of tissue between them altogether 

 devoid of nerves. Now if we apply any stimulus directly 

 to the cornea, as for example, a red hot needle, or lunar 

 caustic, the district which is thereby set in morbid action 

 by no means corresponds to the distribution of any nerve. 

 It once happened to me with a rabbit that the cautery 

 lighted precisely upon a nervous filament, but the mor- 

 bid action remained confined to the immediate vicinity 

 of this spot, and by no means spread over the whole dis- 

 trict appertaining to the nerve. 



It is therefore utterly impossible, even if observations, 

 like those on cartilage which I have laid before you, 

 are not allowed to have any weight, not to admit that 

 the phenomena of irritation in parts supplied with 

 nerves are in no respect different from those which 

 occur in nerveless parts, and that the immediate effects 

 essentially depend upon the enlargement and tumefac- 

 tion of the surrounding elements, so that when there are 

 many of them, a visible swelling of the whole part is 



