branch of the spinal accessory is a motor nerve. We found that when it was embraced firmly within the forceps, or tied tightly soon after it had emerged from the foramen lacerum, the animal gave indications of suffering* ; but an experiment of this kind does not enable us to decide whether these sensiferous filaments were originally contained in the accessory, or were derived from the neighbouring nerves. Mr. Shaw has detailed an experiment to show that the movements which it imparts to the sterno-mastoid, and to the trapezius are not voluntary, but respiratory:I- In our experi ments, and in those subsequently performed by Bernard, these muscles acted in unison with the muscles of respiration after the spinal accessory nerves had been divided.
While all experimenters agree that the ex ternal branch of the accessory is chiefly if not entirely composed of motor filaments, they have arrived at discrepant conclusions re garding the functions of the internal branch. Volkmann t, Van Kempen §, and Stilling 11, observed no movements of the muscles in which the internal branch of the accessory is distributed, on irritating the roots of this nerve within the cranium ; while in those of Bischoff, my own, those of Valentin Lon get**, Hein ft, Morganti tt, and Bernard §§, partly consisting oi irritating the roots of the nerve within the cranium after death, and partly, as in those of Bischoff, Longet, Mor ganti, and Bernard, by lesions of the nerve in living animals, and observing their effects upon the movements of the muscles „in which it is distributed, proofs of its being a motor nerve were believed to be obtained. We
think that this evidence is sufficiently strong to justify the belief that the internal branch of the accessory does contain motor filaments; but it is at the same titne highly probable that it is partly composed of sensiferous and afferent filaments, and if so, its constitution must be similar to the vagus nerve, with which it be comes so closely incorporated. In the art. PAR VAGUM, sufficient proof has been ad duced to satisfy us that the opinion that the spinal accessory furnishes all the motor fila ments contained in the trunk of the vagus, is no longer tenable.
(John Reid.)