( 314 
a= awe = = „va - = En 
El REI Oe En REE 
Fig. 16. 
A. 
B. 
C. 
Et 1 eee 
EME NE DES RS AER OIE A 
2 y | 4 Rn Es 4 
re m ot ee ge a a ee nr ee B 
Nes is Tt ent 4 ee oe Geen ne 
The ranks of the dermatomata towards the mid dorsal line. y is representing that part of the ceztra/ area overlapped by 
a neighbouring central area, and z that part of the ceztral area overlapped by two marginal areas. (Drawn for the 
special case of Dog XV, see fig. 16). 
If in isolating one dermatoma the sensible area is equivalent to the analgetic areas of two dermatomata, then it follows : 
at+y=—%r+y or e=y 
or in isolating two dermatomata, 27 —- 37 is equivalent to the analgetic areas of three dermatomata 32 + 27 etr., 
provided the marginal areas remain smaller than the central area. 
Above each dermatoma the curve of sensibility has been traced. The thick tracing represents the threshold that has to 
be passed, to make any “sensation’”’ possible, 
The addition of the curves in B presenting a schema of sensation along the mid-dorsal line. From this schema may be 
deduced directly the copsequences for sensation, e.g. curve a if one root is cut through, 4 if one root left intact is 
situated between two sectioned roots above and two sectioned roots beneath it etc. 
