(From the Physiological Laboratory, University of Edinburgh.) 



Secondary Degeneration following Unilateral Lesions 

 of the Cerebral Motor Cortex. 



By 

 Sutherland Simpson, M. D. ; B. Se. 



(With Plates XVI, XVII and 5 Figures in the Text.) 



The following paper ^), which in a more extended form was sub- 

 mitted for the degree of M. I), of the University of Edinburgh last 

 July contains a record of the results of a number of experiments, 

 performed on cats and monkeys. The reseai'ch was undertaken at the 

 suggestion of Professor Schäfer, to whom I am much indebted for advice 

 and assistance during its prosecution, and its primary object was to 

 determine the path pursued by the fibres of the pyramidal tract, in their 

 course from the cerebral motor cortex to their termination in the lower 

 levels of the brain and spinal cord, but more particularly their mode of 

 ending in relation to the nuclei of the cranial motor nerves in the mesen- 

 cephalon, pons, and medulla oblongata. Although this — the motor 

 path — has been more carefully investigated, and is probably better 

 understood than any other tract or path in the central nervous system, 

 still much remains to be discovered concerning it, more especially with 

 regard to its terminal connections. In his book on "The Nervous 

 System" (1900) Barker [J] says: — "The exact placée where the fibres 



^) An abstract of tliis pajun' was read Ijoforc the Physiological Society on 

 July 20»i 1901 and [niblislied in tin; .loiinial ot Physiology. Vol. XXVII. Nr. 142, 

 p. 10. 



