> 
geeemuaen 
‘ 
( 273 ) 
The marginal area possesses too great a threshold-value to preserve 
any perceptible sensation when isolated. Because this part does not 
possess any sensation, as long as it is functioning separately (without 
assistance from neighbouring central or marginal area’s) it cannot 
be demonstrated by isolation. 
Secondly, the transversal division that may be observed and 
the manner in which the dorsal piece of dermatoma presents 
itself as “ultimum moriens”, compels us to accept for the 
central area at least two maxima of sensation, one situated next 
to the mid-dorsal line, the other next to a lateral line of demarcation. 
If therefore the intensity of sensation is expressed in ordinates, that 
will rise higher, in proportion as sensation is longer preserved, on 
abscisses, taken on axes parallel to the mid dorsal and the mid-ventral 
lines, then those thus formed eurves situated to the left (a, figure 8) 
represent the sensation in the central- and marginal area’s. If taking 
the axisline of the central area for absciss, the intensity of sensation 
is put thereon as ordinate, then the two-topped curve J, will represent 
the sensation in this axisline. Both groups of lines then represent 
a schema of the distribution of sensation in the dermatoma. 
This unequal distribution of sensation in the dermatoma is the 
more remarkable, because already Vorer believed to have demon- 
stratel by means of anatomical proceedings a lateral minimum of 
innervation. 
Finally we are bound to conclude that every bunile of roots exerts 
an influence on the whole central area, as this area can preserve 
sensation over its whole extension, it making no difference whether 
root-bundles situated cranially or caudally have been sectinoned. 
That in reality every bundle of roots exerts its influence on the 
