321 
Physiology. — “The Structure and Overlap of the dermatomes of 
the hindleg with the cat’. By Dr. S. pr Borr. (Communicated 
by Prof. G. van RIJNBERK). 
(Communicated in the meeting of May 27, 1916) 
I applied the same method that I made use of for the determi- 
nation of succeeding dermatomes in the thoracic-lumbar region, for 
fixing the lines of demarcation of the dermatomes of the hindleg. 
If we want io apply this method to the lower part of the spinal 
cord, we have to overcome a difficulty. 
From the 5'° lumbar root in a distal direction the succeeding 
roots are closely connected. At their origin from the spinal cord 
these roots are consequently not separated from each other, as is 
the case with all roots originating higher. 
Consequently I acted as follows: The lumbar-sacral part of the 
spinal-cord was laid bare under ether-chloroform narcosis, the dura 
was split lengthwise. Then I sought the 4" lumbar root. | moistened 
then the spinal cord round the place of entrance of this hind-root 
with a solution of sulphate stryehnini (1 °/,) coloured by methylene- 
blue. Sometimes the 3° lumbarroot had previously been cut. When 
the cat had then awaked ‘from the narcosis, the hyperreflectory 
field of lumb. IV was indicated on the skin with water-colour. 
Then this hindroot was cut under narcosis and at the place of egress 
of the following hindroot (lumb. V) the spinal cord was moistened 
with a solution of strychnine. Special care was taken, that in a 
distal direction the spinal cord was not moistened past the last 
radicularis of !umbalis V. Then the line of demarcation of this field 
was determined and marked on the skin. Every time different colours 
were made use of for the different fields. The succeeding root was 
then treated in the same way, till all following dermatomes of the 
hindleg, as far as sacralis 1 or 2 included, had been obtained. When 
I determined in this way the dermatomes, it is certain that the 
proximal limits could be obtained more accurately than the distal 
ones. The spinal cord round the proximal radicularia of each root 
can always be sufficiently moistened with a solution of strychnine, 
because the preceding root had been cut. In a proximal direction 
I] never ran the risk of moistening too much or too little. I was 
not so certain however with regard to the distal radicularia. Though - 
I moistened here as carefully as possible with a tapered piece of 
cottonwool the spinal cord to just behind the place of entrance of 
the last radicularis of each root, the uncertainty always remained 
| HEN 
Proceedings Royal Acad. Amsterdam. Vol. XIX. 
