VESSEL-, NERVE-, AND CELL-TERRITORIES. 283 



vessel does not shoot up until later and forces its way 

 into the branches when they have already attained a cer- 

 tain size. It is not the vessel which pushes out the parts 

 by its development, but the first signs of development 

 always show themselves in the connective tissue of the 

 papilla. The study of the conditions of the skin therefore 

 affords special interest to those who wish to devote them- 

 selves to the critical examination of the doctrines held 

 concerning general pathology. And first with regard to 

 the neuro- pathological views, it is quite inconceivable 

 how a nerve which lies in the middle of a whole group 

 of nerveless parts, can contrive to force a single papilla 

 from among this group, with which it has not the slightest 

 connection, into a state of pathological activity in which 

 the remaining papillae of the same nerve-territory take 

 no share. Just as difficult is it, in the diseases of non- 

 vascular papillae, to find an explanation which shall 

 accord with the views of a humoro-pathologist. Even 

 when in a vascular papilla the different cell-territories 

 attain different states, these would not admit of a ready 

 explanation, if we were to regard the whole process of 

 nutrition in a papilla as directly dependent upon the 

 general condition of the vessel which supplies it. 



Similar considerations might be entered upon with 

 regard to all points of the body. Still we have in the 

 skin a particularly favourable example for demonstrating 

 how very incorrect it is to regard all vessels as subject 

 to a particular nervous influence. There are a number 

 of vessels which are entirely removed from the influence 

 of all nerves, and, if we still confine our attention to 

 the skin, the influence which a nerve is in a condition to 

 exercise, is limited to this, that the afferent artery, which 

 supplies a whole series of papillae in common (Fig. 44) 

 may by its means be brought into an altered condition, 

 so that a contraction or dilatation, and in correspondence 



