748 
As it is known W. and v. R. indicate the overlapping of the central- 
1 : 
area as 5 of the extent at the d. d. Further they found, in some 
of their eases, that the width of the analgic zone, the consequence 
of the cutting of two roots, was as wide at the d.d. as the sensible 
zone of one isolated root. 
Let us now compare the results of the strychnine-segmentzones. 
With regard to the proportion of the width of one total segmentzone 
to that of the aveflectory zone of two cut roots we see that the 
proportion is here 30:15, thus instead of 1 : 1 they bear a proportion 
of 2:1. Of greater importance. however is the overlapping of the 
strychninezones ir their entirety, or, where they have taught us to 
consider them, identical with the theoretical dermatomes, the over- 
lappings of the entire rootzones. W. and v. R. could not determine 
them, as is self-evident, because they always found large ““marginal area”. 
If we apply now the method of caiculation of the covering as 
indicated by the above-mentioned authors we find, if we call the 
overlapped field of the root-zones v and the not overlapped part y, 
that at the d.d. holds for the whole hyperreflectory zone 
2c + y= 35 m.m. 
and the areflectory zone must be expressed as: 
2y + 2=—11 mm. 
From this we can calculate the values of v and y 
20+ y= oD 2u+y= 105:3 vt 2y 00 
2y+te=11 my 46:3 et y= 46:3 
du + dy = 46 7 59:3 y =d: 
From which follows that 
Tiye 
13 2 
y= =d. 
d 59 9 
If now we suppose the whole root-zone = 1, then is 
4, 
20 =d 5 1, consequently 162 = 9, and «= Te 
From this follows that the rootfields cover each other at the d.d. 
9 9 
for i W. and v. R. had estimated it at about qe which agrees 
J 
pretty well with my result. 
From the construed figure (fig. 4) it appears that in the dorsal 
trunkskin, parts are alternately provided for by two and by three 
