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Physiology. - "On the segmental shin-innervation by the sym- 

 pathetic nervous system in vertebrates, based on experimental 

 researches about the innervation of the pigment-cells in flat 

 fishes and of the pilo-motor muscles in cuts.'' By Dr. (i. van 

 Ki.jniïkrk. (Communicated by Prof. C. Winki.kk.) 



(Communicated in the meeting of October 2G, 19Ü7.) 



We possess numerous, though dispersed, data, obtained either by 

 means of experiments on animals or founded on clinical observations, 

 tending all to confirm the opinion, that in vertebrates and in man, 

 the efferent nervefibres, intended for the skin, which are conducted by 

 the grey connecting branches from the lateral column of the N. 

 sympathicus towards the mixed spinal nerves, are distributed within 

 the area of the skin that is supplied with afferent fibres by the 

 spinal nerve. As moreover, in general, save slight deviations, the 

 efferent sympathetic fibres of the grey connecting branches have 

 their origin in the ganglia of the column in which these branches 

 apparently originate, we may assume that the zones of the skin, 

 innervated by the ganglia of the sympathetic column are nearly 

 identical in their distribution with the zones of the skin, supplied 

 by the different corresponding spinal ganglia. Less numerous are 

 the data about the relative extent of the sympathetic ami spinal 

 zones of the skin; but indirect indications apparently support the 

 view that the zones of the skin innervated by the spinal ganglia 

 arc more extensive than the zones of the different correspond i un- 

 sympathetic ganglia. With this reservation however we apparently 

 may hold it very probable, that the innervation of the skin both by 

 the sympathetic and by the spinal ganglia is taking place according 

 to the self-same morphological scheme. Hitherto nevertheless no 

 direct proofs have been given by demonstrating on the self-same 

 object the relative distribution and extent of these innervation-areas. 

 It has been my purpose to do this now by means of a few simple 

 experiments. 



A. The sympathetic innervation of tin pigment-cells and the 

 spinal innervation for sensibility of the skin m flat fishes. 

 Since the elaborate researches of (1. Poüchet l ) we know that in 

 several species of fishes the phenomenon of the variability of colouring 



') G. Pouchet. Des changements de coloration sous l'intluence des nerts. — 

 Journal de l'anatomie et de hi physiologic. Tome 12 p. 1 — 90, and p. 113 165, 

 Parijs 1S7G. »• 



