(58 



Mr. C. S. Sherrington. 



[Mar. 17 r 



unusually thick the additional fibres in it are not all of them, perhaps 

 none of them, used to supply the muscles usually supplied by the 

 root, but are used to supply altogether other muscles not usually 

 supplied by the roots ; that the distribution of the fibres of a root is 

 not to one group of muscles, but is to several groups, which are often 

 not related to each other in function ; that antagonistic groups are 

 often supplied by one and the same root. 



Three years after the experiments by Eckhardt, and also under 

 Ludwig, Peyer's* experiments on the brachial plexus of the rabbit 

 were made. As Krause, in 1861, f repeated Peyer's work on the same 

 limb and the same species, the results of both may be here referred to 

 together. The muscles of the limb each receive nerve-fibres from two, 

 in some cases three, spinal roots ; usually the contraction of a muscle 

 on excitation of the spinal roots innervating it is obviously different in 

 degree for each root : the same spinal root does not always supply in 

 different individuals the same muscles ; the further the position of 

 a spinal root from the head, the nearer the muscles it supplies to the 

 distal end of the limb ; the peripheral trunks of the limb plexus are 

 themselves plexuses of root-bundles. In 1881 Ferrier and Yeo£ 

 confirmed the above results in experiments on the spinal roots of the 

 monkey. In addition to their experiments on the brachial plexus, 

 they performed four complete experiments on the lumbo-sacral roots. 

 Unlike Kronenberg, Eckhardt, and others, they do not seem to have 

 met with any variation in the results obtained. They revived the view 

 that the efferent distribution of each spinal nerve is based on its phy- 

 siological function, and that the movement resulting from the excita- 

 tion of a root is that of a highly coordinated functional synergism. 

 Some months later Paul Bert and Marcacci§ published experiments 

 on the lumbar roots of the cat and dog. They concluded that (i) each 

 root produces a coordinate movement, and consists of fibres function- 

 ally associated; (ii) when a muscle is functionally divisible its root- 

 supply is multiple. 



In 1883Eorgue and Lannegrace|| published a research on the limb 

 plexuses of the cat, dog, and monkey. The ' Comptes Rendus of 

 the following year contain their reports. As to the lower limb, their 

 account is prefaced by a remark that the highest lumbar root of man 

 is tripled in the dog and monkey. What species of monkey was used 

 is not mentioned in tjie ' Comptes Rendus.' In Macacus the 5th 

 lumbar root is analogous not to the 3rd of man, but to the 4th, and- 



* £ Arch. f. Eat. Med.,' II, toI. 4, p. 67, 1853. 



f ' Beitrage zur Anat. der Oberen Extremitat,' 1861. 



X ' Roy. Soc. Proc.,' 1881. 



§ * Soc. de Biol.,' July, 1881. 



|| ' Ga*. Hebd. des Sci. Medic, de Montpellier,' 1883. 

 IT « Comptes Rendus,' 1884, vol. 98, pp. 829, 685, 1068. 



