Page:Proceedings of the Royal Society of London Vol 60.djvu/270

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The following researches were carried out in consequence of suggestions made 'to me by Professor Victor Horsley, F.R.S., with the view of throwing light upon the degree to which certain movements, or, speaking more precisely, sensori-motor (kinaesthetic) phenomena are represented in any given segment of the lumbo-sacral region of the mammalian spinal cord, and further of determining what relationship exists between the representation of one movement and that of another. Of methods suggesting themselves for this investigation the one selected was direct excitation of the anterior or posterior roots or of the spinal cord itself.

A series of laborious investigations has been carried out to determine the localisation of certain movements and the physiological relationship of various muscles in and to definite segments of the spinal cord, by Ferrier and Yeo, Bert and Marcaeci, Forgue, Sherrington, and Russell, the method of which was limited (controlled by exclusion experiments) to stimulation of the motor roots. I am only aware of one antecedent localisation experiment (by Sherrington) carried out by stimulation of the posterior roots; nor can I find any record of the direct excitation of the surface of the cord for investigating the localisation of movement.

(a) Species of Animal.—The animals chiefly employed were the dog and monkey (Macacus sinicus and rhesus).

(b) Anaesthetic.—The narcotic agents used wrere morphia and ether or, in the monkey, ether alone.