400 



PHYSIOLOGY 



in 



TI 



IV 



VII 



VI 



FIG. 176. Diagram of sections of the spinal cord of the monkey showing the position 

 of degenerated tracts of nerve fibres after specific lesions of the cord itself, the 

 afferent nerve-roots, and of the motor region of the cerebral cortex. (SCHAFER.) 

 (The degenerations are shown by the method of Marchi.) The left side of the 

 cord is at the reader's left hand. 



I. Degenerations resulting from extirpation of the motor area of the cortex of 

 the left cerebral hemisphere. 



II. Degenerations produced by section of the posterior longitudinal bundles 

 in the upper part of the medulla oblongata. 



III. and IV. Result of section of posterior roots of the first, second, and third 

 lumbar nerves on the right side. Section III. is from the segment of cord between 

 the last thoracic and first lumbar roots ; section IV. from the same cord in the 

 cervical region. 



V. to VIII. Degenerations resulting from (right) semi-section of the cord in 

 the upper thoracic region. V. is taken a short distance above the level of section ; 

 VI. higher up the cord (cervical region) ; VII. a little below the level of section ; 

 VIII. lumbar region. 



