The Excitable Cortex of the Cliinipanzee, Oranor-Utan, and (Joiilla 199 



the amount of tlie degenerations, eitlier contralateral or ipsilateral, in their 

 descent alontf the cord so far. On rcachinj; the lumbar reirion the contra- 

 lateral deorfneration shifts out laterally so as to leave the deepest region 

 of the white column next to lateral iiorn, and to occupy about the dorsal 

 three-fourths of the margin of lateral column. Hy the level of interval 

 between 4th (last) lumbar and 1st sacral seirnients a threat diminution in 

 the extent of the degeneration is obvious : the contralateral has assumed a 



i-M. 



4/-/< 



Fig. 25. — Outlines ( x 3 iiat. size) of cioss-seetioiis of the spinal cord ot cliimpanzee, 

 showing the degenerations following on ablation of jiait of the leg area from the 

 left hemisphere ; ablation-experiment 4. 



comma-shaped form (tig. 25), the tail of the comma lying along the margin 

 of the lateral column. The deeper part of the degeneration is in contact 

 with grey matter only along the dorsal horn. Of the ipsilateral degenera- 

 tions, the one in ventral column is no longer present, and that in lateral 

 column lies in a situation corresponding with that of the head of the comma 

 of degeneration on contralateral side. 



In the lurabo-saeral enlargement, especially in the 4th lumbar and 1st 

 sacral segments, the ventral horn of grey matter shows on the right side a 

 fine-fibre degeneration similar to that mentioned under the unilateral arm 

 area lesion. 



