( 338 ) 



irilmiion of the pilo-motor and of the sensory fibres having their 

 course in the dorsal nerve-branches of the skin. This may be done 

 in a very simple way. 



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Fig. 5. 



Scheme of the course of the (post ganglionic) pilomotor- and of the sensory 



nerve-fibres toward the skin of the trunk-area in cats. 



M.S. = medulla spinalis. — r.d r.v = dorsal and ventral root. — N.S. = mixed 

 spinal nerve. — d.p.d.-d.p.o. = dorsal and ventral trunk of the spinal nerve.. — 

 r.e.d. = dorsal ramus cutaneus. — C.L. = lateral column of the N. Sympathicus. — 

 g.sp.-g.si. = ganglion spinale, sympathie ganglion. — r.c. — grey connecting branch 

 _ _ define the course of the spinal sensible fibres .... that of the pilo- 

 motor fibres. 



1 obtained this scheme by defining first by means of Sherrington's 

 method of isolation the surface of the sensible area innervated by a 

 certain skin-branch and next by the stimulus of an induced current 

 applied to the same branch, causing the surface of the skin-area, 

 innervated by the pilomotor fibres from this branch, to become visible. 

 In order to do so, the hair on the trunk of the cats I made use 

 of, were first cut uniformly by means of a so-called tondeuse to a 

 length of about half a C.M. Afterwards, under narcotics and with 

 aseptic precautions (as far as possible, the skin not being shorn) a 

 longitudinal incision was made in the skin along the mid-dorsal 

 line, and the skin was folded back to both sides. The connective 

 (issue having been prepared the series of dorsal skin-nerves was in 

 most cases pretty plainly distinguishable, and it was very easy to 

 choose a definite branch for isolating and to section the three branches 

 lying next to this one both cranialward and caudalward, either after 



