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Leyton and Sherrington 



relatively to that of the lateral column remain about the same as higher 

 up. They also retain about the same proportions relatively each to the 

 other. In the ipsilateral ventral column a " direct pyramidal tract " 

 degeneration is still marked, but its area is smaller, and is confined to the 

 deeper part of the side of the ventral fissure. Below the brachial enlarge- 



FlG. 20. — Outlines ( x 3 nat. size) of cross-sections of the bulb and spinal cord 

 of cliimpanzee, showing the pyramidal-tract degenerations after lesion in 

 the arm area of the left hemisphere, in ablation-experiment 1. 



ment the deo-enerations are seen to have become much smaller. In the 

 mid-thoracic region no degeneration is detectable in the ipsilateral lateral 

 column, but in ipsilateral ventral column a few degenerated fibres are still 

 obvious near the ventral lip of the fissure. In the contralateral cord-half 

 a faint scattered degeneration is still obvious occupying the usual pyra- 

 midal-tract area. This latter degeneration is still detectible, although 

 much less, at the 13th thoracic level, but lower than that is not recognis- 



