22 



Mr. J. S. Risien Russell. 



[Mar. 3, 



II. " An Experimental Investigation of the Nerve Roots which 

 enter into the formation of the Brachial Plexus of the 

 Dog." By J. S. Risien Russell, M.B., M.R.C.P. Com- 

 municated by Professor Victor HoRSLEY, F.R.S. Received 

 February 18, 1892. 



(From the Physiological Institute of Berlin and the Pathological Laboratory of 

 University College, London). 



(Abstract.) 



The subject is introduced by an allusion to the attempts that have 

 been made by anatomists to determine the f emotional relationships 

 between the nerve roots and groups of muscles they supply, in which 

 connexion the work of Krause, Schwalbe, Herringham, and Paterson 

 are cited. A brief reference is made to the observations of Erb, 

 Duchenne, Knie, and Thorburn, after which the author refers to 

 the experimental work that has been done in this field by Muller and 

 Van Deen, Kronenberg, Panizza, Peyer, Krause, Terrier and Yec, 

 Bert, Marcacci, and Forgue. The anatomical accounts of the 

 brachial plexus of the dog as given by Ellenberger and Baum, 

 Ohauveau and Arloing, and Forgue are quoted, the discrepancies which 

 exist between these different accounts pointed out, and the author's 

 own experiences in this connexion, differing in some points, while 

 agreeing in others, with the descriptions given by these observers, 

 are detailed. 



He then proceeds to explain his methods of experimentation, which 

 consisted in : — 



1. Observation of the compound movements in the fore limb of the 

 dog by electrical excitation of the peripheral end of the whole of a 

 cervico- brachial nerve root which had been previously exposed and 

 divided. 



2. Minute differentiation obtained by electrical excitation of the 

 individual bundles composing such a nerve root. 



3. Direct observation (after dissection) of the muscles thrown into 

 action by electrical excitation of the separate nerve roots. As a 

 corollary to this, the question as to whether or no a single bundle of 

 fibres representing a single simple movement in a nerve root ever 

 remains distinct in its course to the muscles it supplies, without 

 inosculating with other nerve fibres, is dealt with. A further point 

 determined is whether, when a muscle receives nerve fibres from more 

 than one cervico-brachial nerve root, both nerve roots supply fibres to 

 one and the same muscle fibre or not. 



4. Alteration in the action of the fore limb in progression or in 

 standing, evoked by section of a nerve root or roots. 



5. Influence of section of a root or roots in excluding part of a 



