1141 
This is therefore of great interest because in this way the factor of 
variability is excluded, which certainly plays a part, when we use 
the separate dermatomes of different animals for it. We can also 
apply this method to ascertain whether there is any connection 
between the pigmentation of the skin and the dermatome-covering, 
and what connection there exists between these. The selection of 
such animals as are fit for this purpose, must, in my opinion, lead 
to a reliable solution. The connection that might exist between the 
lines of LANGELAAN and the arrangement of the dermatomes can 
now be studied more directly. My experiments prove with certainty 
what was already demonstrated by KresseNs for one case viz. that 
not only two adjoining dermatomes cover each other, but that there 
exists also covering between two that are separated from each other 
by a third one. I found even also at the ventral side covering of 
four dermatomes. Now the question rises whether these covering- 
spots of more than two dermatomes correspond with those parts of 
the skin, where under normal conditions hyperalgesy exists. 
This problem can now likewise be more directly studied. 
Fig. 5 gives a representation of the mutual covering of the root- 
fields in the thoracal region. 
The spinal-cord in the thoracal region of this cat was first 
laid bare to a large extent. First | moistened the spinal-cord behind the ' 
13 thoracal root with a solution of sulf. strychnine (1°/,). The 
hyperreflectory field that I discovered, is found between the lines 1 
and 4. Then I cut the 13" thoracal-root through and determined 
the field of thoracalis 12 in the same way. | now cut every time 
the root of the determined field and looked for the field that follows 
immediately in a frontal direction according to the strychnine method. 
In this way [| found the field of ‘ 
thoracalis 13 between lines 4 and 4 
5 12 EN Ei ZO 
DE 11 ke SSS 
3. 10 - ne ee ow wll) 
EE 5) a ee (ee are Lel 
ke 8 ze Arda OREL), 
Two fields viz. those of thoracalis 11 and 10 are represented here 
with the covering of the adjoining fields. Let us now make a close 
inspection of the field of thoracalis 11. Its posterior boundary is 
constituted by line 8, the anterior boundary by line 8. Line 4 is 
the anterior boundary of thoracalis 13 and line 6 that of thoracalis 12. 
