1905.] 



Corel of the Macaque Monkey. 



133 



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i n nr iv v vi vu i n m iv i n m 



JL umbar Sea: reel Coccygeal 



Chart XVII. —Curves showing the Eatio of the Dorsal Columns (P, broken line) and of 

 the Ventro-lateral columns (A, line and dot) to the Dorsal Horns (D). 

 The dorsal horns taken as unity in each cross-section of the cord. Mean results are 

 plotted (Table XVIII). The abscissae denote spinal nerve regions, the ordinates ratio at 

 the corresponding regions. 



(«) Eatio d °*' sal ° olumns (?) (Chart XVII, Table XVIII). 

 dorsal horns (D) 



The ratio °] sa ^ ^ umns ( P) decreases from the first lumbar region to the 

 dorsal horns (D) 



end of the cord. 



The decrease in ratio is very rapid from the first lumbar to the first sacral 

 region. It occurs chiefly in the fifth, sixth, and seventh lumbar regions, and 

 more particularly in the fifth and sixth. The ratio remains very much the 

 same from the first to the third sacral region. 



/7\ t> ventro-lateral columns (A) /n , , „ TTrT rn 



(b) Eatio r- )— (Chart XVII, Table XVIII). 



dorsal horns (D) ' 



m, , • ventro-lateral columns (A) ■, „ , , . , , , 



Ine ratio — I decreases from the first lumbar region 



dorsal horns (D) 



to the first coccygeal, and increases slightly in the lower coccygeal regions. 



The decrease is slight from the first to the fourth lumbar, but very rapid 

 from the fourth to the seventh lumbar region. 



The ratio never becomes as 1 : 1. 



