740 
Physiology. — “Form and function of the trunkdermatome tested 
by the strychnine-segmentzones”’ *). By J. J. H. M. Krpssens. 
Communicated by Prof. WINKLER. 
(Communicated in the meeting of October 26, 1912). 
The theoretical trunkdermatome of man ard mammals is a trape- 
zium, the short basis of which lies in the dorsal diameter, and the 
long basis of which lies in the ventral diameter. This statement dates 
already from Turck, who called the attention to the fact that dorsally 
a same number of posterior roots provides for the skin covering the 
thoracal-vertebrae, whilst ventrally they do so for a much larger 
part of the skin, extending from the manubrium sterm to the sym- 
physis pubica. 
It seems that the anatomically prepared dermatomes (Bork ®), 
KROSSER and Frönrien *)) support this view. 
The root-fields experimentally fixed according to the ‘remaining 
aesthesia’”’ method, that Snerrincron *) found with Macacus rhesus, 
have likewise a form answering to the theoretically postulated -one. 
SHERRINGTON writes, that the string formed by the dermatomes on the 
trunk is, “somewhat wider near its ventral than at its dorsal end”. 
And passim: “each zone is narrowest at its dorsal end’. Yet 
SHERRINGTON remarks that the periphery of the dermatomes feels 
stronger than the central part, so that going from the border towards 
the centre for the fixation of sensibility, occasionally the sensibility 
suddenly appears to become much sharper. 
A similar fact was stated for the dog by C. WINKLER and vaN 
RuNBerK *). They saw namely that the sensible isolated zone generally 
deviated in extent and form from the theoretical dermatome. These 
1) According to investigations made in the physiological laboratory of the Uni- 
versity of Amsterdam. 
2) L. Bork, Die Segmentaldifferenzirung des menschlichen Rumpfes und seiner 
Extremitäten. I—IV, Morphologisch Jahrbuch Bd. XXV. XXVI, XXVIL XXVIII. 
Leipzig 1897—1900 and: 1. BOLK. Een en ander uit de segmentaal anatomie van 
het menschelijk lichaam. Ned. Tijd. v. Geneeskunde. Amsterdam. 1897. Vol. L. p. 
982. Vol. II. p. 366. 
3) O. GROSSER und A. FROHLICH. Beitr. z. Kenntniss der Dermatome der mensch- 
lichen Rumpfhaut. Morphol. Jahrb. XXX. S. 308. Leipzig 1902. 
4) C. S. SHERRINGTON. Examination of the peripherical Distribution of the fibers 
of the posterior Roots of some spinal nerves I Transactions of tle Royal Society 
of London. B. Vol. 184. p. 691. London. 1892. i 
5) CG. WINKLER and G. vAN RuNBERK. On function and structure of the trunk- 
dermatoma I-IV. Proc. of the K. Akademie van Wetenschappea te Amsterdam. 
1902 —1905. Amsterdam, and: CG. WINKLER. Ueber die Rumpfdermatome. Ein 
experimenteller Beitrag z. Lehre der Segmental-Innervation der Haut. Monatschr. 
f. Psychiatrie und Neurologie, Bd. XIIL S. 161. Berlin. 1993, 
