174 PHYSIOLOGY OF CENTRAL NERVOUS SYSTEM. 



tions, but these fibers in the cerebellospinal tract end in the cere- 

 bellum, an organ which, so far as we know, gives rise to no con- 

 scious sensations. To speak of them, therefore, as muscle-sense 

 fibers may be somewhat misleading, and it may be better to follow 

 the plan of designating them as the non-sensory afferent fibers 

 arising from tissues beneath the skin, such as the muscles, the 

 tendons, and the ligaments round the joints. The superfi- 

 cial anterolateral fasciculus has been the subject of some ex- 

 perimental study from the physiological side, but the results 

 have been negative. Clinically, the tract may be involved 

 in pathological or traumatic lesions of the lateral funiculi. Gow- 

 ers* gives a history of some such cases, which lead him to be- 

 lieve that this tract constitutes a pathway for pain impulses, 

 and this view or the view that it conducts the impulses of both pain 

 and temperature has been more or less generally accepted. Entire 

 confidence, however, cannot be placed in this conclusion, since the 

 lesions in question were not strictly confined to the fasciculus 

 in question, although clinical evidence indicates that the fibers 

 conveying impulses of pain or of pain and temperature lie in the 

 ground bundles in the neighborhood of this tract. The only posi- 

 tive indication that we have concerning the physiological value of 

 this specific tract of fibers is given by their histology in the fact that 

 they end, for the most part, in the cerebellum. The cerebellum, 

 we know, may be removed in dogs and monkeys without loss of the 

 sensation of pain, temperature, or touch, and this fact speaks 

 strongly against the view that either the cerebellospinal or the 

 superficial anterolateral fasciculus is concerned in the conduction of 

 these cutaneous sensations. From a physiological standpoint we 

 should be inclined to believe that both of these tracts conduct non- 

 sensory afferent impulses from the tissues lying under the skin, 

 particularly from the muscles, tendons, and joints. It would seem, 

 therefore, that all the long ascending tracts in the posterior and 

 lateral funiculi of the cord may be made up of fibers of muscular 

 sensibility, using this term in a wise sense to include the deep 

 sensibility of the joints, tendons, and muscles. The immense 

 importance of muscular control in the maintenance of life and in 

 defense against enemies may explain, upon the doctrine of the 

 struggle for existence, why the long paths should have been devel- 

 oped first in connection with this sense. 



The Spinal Paths for the Cutaneous Senses (Touch, Pain, 

 and Temperature). From the facts stated in the last two para- 

 graphs it would seem probable that the spinal paths for touch, 

 pain, and temperature must be along the short association 

 tracts of the proper fasciculi of the lateral and anterior funiculi. 

 There is evidence from the clinical side that the paths of con- 

 * Cowers, "Lancet," 1886. 



