(522) 
Besides the inverted direction of 4, there exists still another diffe- 
rence between the ranks of the dorsal and those of the ventral central 
areas, because experiment shows, that by sectioning one root 
insensibility will be roused at the mid-ventral, but not at the mid- 
dorsal line. At the mid-dorsal line therefore the first 2 does not 
exist. Insensibility in that part is counteracted by marginal areas 
overlapping one another, which is not the case at the mid- 
ventral line. 
In the lateral part on the contrary the central areas are ranged 
more closely than at the mid-dorsal line. They overlap one another 
farther, even until more than midway. Still the central area may 
be here again expressed by z + 2y, it being understood however 
that in this case too « and y are set in the same direction. But now 
« will be counted in cranio-caudal direction, and obtain consequently 
a negative value. Therefore the value of the central area will be 
in the lateral part 2y—z« etc. 
The results, obtained by applying these formulas, are very simple. 
They may be demonstrated by means of Observation III (Series 
II, Nr. 1), the same observation put to use already in our former 
essay, where the sensible area corresponds with two roots left intact, 
whilst three analgetic areas (two to the right and one to the left) 
in their turn correspond each with two sectioned roots. 
The central area in this case is: 
Mid-dorsal line. Largest breadth of the central area. Mid-ventral line. 
. 
2 
2x-+ 3y = 4.6 pets? 
2 
thence 
3.8 2 
en (ave Dt stats Tae ene cA 
50 a = y= Ne = {0.7 
Ears lonen era | eae | 
or 
2.825 0.8 
RE ,= 53 ka $12 
12.775 log 
wo LOD ART TN Var Te 
