744 
foremost limit of the inner-zone, the eranial limit of the total zone 
soon assumes a course directed more towards cranial, so that the 
cranial outer-zone, in the d. d. scarcely a few mm. wide, is in the 
vy. Gd. 10°iam.-wide, 
The caudal boundary-line continues to run at the d. d. almost 
together with the caudal limit of the inner-zone; it is here hardly 
a few mm. to the outside. Its further course however is like that 
of the cranial limit strongly divergent, consequently here in a strong 
caudal direction, so that, especially in the ventral zone, a wide 
outer-zone appears, which in the v. d. is 21mm. wide. The caudal 
outer-zone is consequently almost twice as wide as the cranial one. 
If we regard now this large extent, and the shape that the total 
strychnine-segmentzone obtains by the addition of the so wide outer- 
zones, we should be inclined to admit that almost the whole theo- 
retical, ideal dermatome has appeared here. If now we remember 
W. and v. R.’s conclusion: 
“Tsoliert man experimentell ein Dermatom so entspricht der erhaltene 
sensibele Bezirk nie weder der Ausdehnung, noch der Gestalt nach, 
dem theoretischen oder anatomischen Dermatom,” ’) then the com- 
bined strychnine-isolation. method applied by me affords doubtless 
better results than the simple “remaining aesthesia method”. For 
under the influence of the strychnine poisoning the limited value for 
the reflexion diminishes so much that there can hardly anymore be 
question of a marginal area in the sense of W. and v. R. 
2. Strychnine-segment zone of Th. XI left. 
After the rootfield of Th. VIIL had in this way been fixed and 
measured, the root Th. XI was isolated in the same way by cutting 
the dorsal roots of Th. XII and XIII, and locally poisoned with 
strychnine. 
The hyperaesthetical zone that appeared here likewise, had a steep 
trapezium shape, and was when the total extent had been reached, 
at the d. d..34 mm., at the v. d. 49 mm. wide. Here the cranial 
limit could however only be fixed, after the Th. VII, isolated in 
the preceding experiment, had been cut. For it appeared that the 
cranial limit of Th XI crossed the caudal limit of Th. VIII in the 
level of its lateral cranial curve. 
a. Description of the central zone. 
The central zone of Th. XI occupies dorsally also again almost 
1) G. VAN RunperK. Versuch einer Segmental-Anatomie. Ergebnisse der Ana- 
tomie. Bd. XVIII. Wiesbaden 1910. S. 544. 
