66 PHYSIC 



of the skin, and the sympathetic nerve terminals in the lining 

 membranes, very much in the same manner as the leaves 

 of a tree say a sycamore are disposed on its terminal 

 branches, which, when looked at from the outside or from 

 above, show an almost complete continuity of leaf surface 

 distribution and arrangement, giving to the tree an appear- 

 ance of solidarity, which is only appreciated at its true 

 value when subjected to scrutiny from underneath or 

 within then it is realised that the disposition of the 

 individual leaves is such as completely to ''slate" the 

 trunk and its branches, the natural seasonal leaf shedding, 

 revealing the same truth negatively. On pursuing the 

 comparison, we become aware that at certain points of the 

 leafy envelope of this sycamore a group of leaves shows 

 a disposition to wither, change colour, and are finally shed, 

 leaving a mark more or less evident amid the prevailing 

 green, which may become a permanent scar should the 

 leaves not be renewed. Very similar phenomena are 

 observed in the disposition of the sensory nerve terminals 

 of the skin, as they lie closely tessellated in its neuro-haemal 

 layer when attacked by eruptive and destructive morbid 

 forces and materies morbi from within the central nervous 

 system, or, if the eruptive displays involve the lining 

 membranes of the body cavities, the same may be said of 

 the sympathetic nervous system. 



The phenomena of diversity of appreciation of sensory 

 stimuli by different areas of the skin and by different 

 points within any one area, in view of the comparative 

 light thrown on the subject by such observations as these, 

 would seem explicable by the varying degrees of intensity 

 with which the various component parts of the nerve 

 terminal expansions are reachable by the stimuli ; thus 

 the outer or peripheral surface of the neural tubules, com- 

 posing the terminal arborisations, must be reached, and 

 respond more quickly and readily than those surfaces 

 representing the sides and under aspects of the same 

 tubules, and hence the explanation of the apparent con- 

 tradictoriness of the results obtained by experimental 

 stimulation of these sensory nerve terminals, and the 

 unsatisfactoriness of the conclusions which have been based 

 on the results. 



