(Zl 
5. Lastly it may sometimes be stated, that only next to the mid- 
dorsal-line some remnant of sensation is left, localised in single spots 
as indicated by fig. 6, surrounded by a broad insensible area. 
fig. 6. 
The part of the dermatoma retaining sensation longest. 
As soon as in the posterior root of the dermatoma, isolated in the 
manner indicated before, one or more bundles are cut through, results 
are obtained similar to those mentioned above and represented in 
fe 2 23,4, 5 and 6, 
The narrowings of the dermatoma-area’s to triangular zones with 
or without transversal division, are also found, if any bundles of the 
intact root are sectioned, it making no difference whether caudal or 
cranial bundles of that root have been cut through. It must however 
be understood, that in proportion as greater experimental ability is 
acquired in isolating the trunk-dermatomata, a simple isolation will 
in most cases offer the sensible dermatema-area described sub. 1 
(fig. 2), whilst the cutting through of bundles in the posterior root 
of this dermatoma generally will present one of the area’s described 
sub 3—5. 
It may thus be rightly supposed that the more or less important 
narrowings, or even shortenings with transversal division of the der- 
matomal area’s, often to be found after simply isolating the dermatoma 
must be accounted for by unintentional lesions of the root left intact 
or of the medulla (profuse hemorraghe, pressure of coagulated blood 
ete). There exists only a difference in degree with the results 
obtained by the intentional lesion, effected by partly cutting through 
the -root-bundles. 
One single spot of the dermatoma, lying adjacent to the mid- 
dorsal-line, preserves sensation longest, in whatever way the operation 
may be made. 
