(523) 
By reconstructing now the ranging of the central areas on this 
dog, a ranging communicated ') already formerly, without however any 
mention then being made of their enlargement in the lateral part, 
fig. 29 is obtained. 
In this figure moreover the curve of sensibility on the central 
area has been designed each time. At the mid-ventral and at the 
mid-dorsal line are designed the addition-curves of sensibility, deduced 
from those curves, and represented in our former communication 
for the same dog by fig. 16 and 18. In the lateral part too 
has been designed on each central area, at the place where its 
breadth is found to be largest, a curve of sensibility (B), rising 
only a little above the threshold-line A, because in this place is 
located the relative minimum of the central area. 
The slight rise above the threshold-line and the large basis of 
this curve, combined with the mutual overlapping of 4 or 5 of these 
curves, are cause that in the lateral part the tops and valleys of 
their addition-curves offer differences of far less importance than 
those found at the mid-dorsal and especially at the mid-ventral line. 
This latter fact promises to become of great interest clinically. 
Already the existence of hyperalgetic bands next to bands of 
diminished sensibility had been demonstrated by Dr. LANGELAAN 2) 
on normal persons and by Dr. BEYRRMAN *) on patients, suffering 
from tabes. Especially with tabes, when in consequence of the 
diminished sensibility the threshold-value rises, and only the tops of 
the addition-curves have preserved sensibility intact (or sometimes 
increased it) the contrast can be striking, on chest and ventral part, 
between the valleys of the curve of sensibility, perceiving pain 
hardly or not at all, and the hyperalgetic tops. In the lateral parts 
of the thorax this difference either does not exist or is only slightly 
pronounced. 
But apart from the differences in sensibility, existing between the 
dorsal part, the lateral part and the ventral part of the trunk, by 
this drawing is shown directly what will happen in the case of one 
or more dermatomata being destroyed. 
When one dermatoma is destroyed, then the dotted area disappears and 
the ventral insensible triangle is formed. This single circumstance is in 
itself sufficient to prove the necessity of admitting the existence of 
1) See: Proceedings of the Roy. Acad. of Sciences. Meeting of Dec. 28th 1901. Fig. 19. 
2) See: Proceedings of the Royal Acad. of Sciences. Meeting of Sept. 29th, 1900. 
35) See: Proceedings of the Royal Acad. of Sciences. Meeting of Sept. 29th, 1900, 
