(519 ) 
These central areas will necessarily suffer their most important — 
reduction in that place where, their breadth being largest, already 
under normal circumstances the sensibility is raised relatively only 
a little above the threshold-value, in the lateral part therefore. 
Consequently there is formed in this case a continuous insensible 
band, denoting the destruction of two roots. This band is found 
to be interrupted in the case of these same roots being simply cut 
through without any more. Still there may be noted instances (in 
Fig. 24 and 25, left side) where after a few days or under especi- 
ally favourable conditions, even directly after-the operation, both 
analgetic bands correspondent ,with two sectioned roots, are inter- 
rupted in the lateral part by the sensible central area. There the 
accordance with the simple sectioning of two roots is found to be 
perfect. 
It may happen however that the central area, either at the 
caudal or at the cranial side, has been damaged by the isolation, 
and that therefore (as is the case in fig. 21 and in fig. 22 for the 
analgetic area correspondent with the 18% and 19 pair of roots), 
there is found a one-sided interruption of the central area by the 
neighbouring analgetic area, whilst it continues to fulfill its functions 
properly on the other side. 
Indeed, with deeply destroying operations it may even happen 
that one of the analgetic areas encompassing a central area, and 
correspondent each with two sectioned roots, begins to interrupt the 
central area — generally a caudally situated analgetic area may do 
this — whilst at the same time on the cranial side the central area, 
properly fulfilling its functions there, may be found interrupting the 
cranial analgetic area. 
This is the case e.g. in fig. 25, right side, where two dermatomata 
have been isolated by sectioning six roots, and where the anterior 
(13) central area shows on both sides the lateral interruption, 
whilst the posterior (16%) central area, probably because the me- 
dulla has been damaged (hindlegs are paralysed), is threatened to 
be interrupted by the analgetic area of the 17 and 18% root, 
which latter interruption however is only half achieved. 
The lateral part of the central area and to all probability of the 
whole dermatoma is its broadest, but at the same time its feeblest 
part. 
The first influence, exerted by the out-growth of the upper extre- 
mities on the higher trunk-dermatomata, is their being pressed into 
one another. The consequence is such as represented in fig. 27, 
left side, 
