(212) 
This spot justly deserves to be called the “ultimum moriens’’ of 
the dermatoma. 
These facts may induce us firstly to distinguish in the dermatoma 
between a central area, having the form of a knotted triangle the 
base of which is lying adjacent to the mid-dorsal-line and the narrow 
side directed towards the mid-ventral-line, and the remainder of the 
dermatoma, extending on both sides (cranio-caudally) of the first area, 
and which may be called the marginal area. The latter may be 
represented by two triangles, whose bases are lying next to the mid- 
ventral-line, and whose tops next to the mid-dorsal-line, whilst the 
central area is enclosed between them (fig. 7). 
Fig. 7. 
This distinction is necessary. The central arca, as it is clearly 
demonstrated in favourable cases by the isolation of the dermatoma, 
is by itself sufficient for sensation, without assistance from the sur- 
rounding dermatomata. The marginal area by itself is insufficient 
for sensation. It can only be made sensible by means of the central 
or marginal area’s of neighbouring dermatomata, by which it may be 
overlapsed. 
Evidently the marginal area is not to be identified with SHERRINGTON’s 
antero-posterior overlapses; for the central area’s too overlap one 
another partly. Still there may be found in SHERRINGTON’s researches 
an indication pointing towards the schema demonstrated here: where 
he states that the periphery of the dermatomata often possesses only 
a very imperfect sensation, and sensation diminishes rapidly from 
the centrum to the periphery. 
