130 Miss M. P. FitzGerald. The Lumbosacral-coccygeal [June 17, 



The relative importance of the dorsal and the ventral horns of the grey 

 substance to the total area of the cross-section of the cord varies considerably 

 between the first lumbar and the third coccygeal regions. This is shown in 

 Chart XVI. 



The calculations were made with the mean figures of each ratio as given in 



Table XVI. The ratio — — ; dorsal horns j n ^he region of 



total area of cross-section of cord 



each nerve is divided by 0-0871, the value of the ratio in the first lumbar 



region, and similarly the ratios ventral hoins arg eae ^ 



total area of cross- section of cord 



divided by - 1171, the value of that ratio for the first lumbar region. 



EBiivvviyiri urn iv i int 



3-4 

 3-2 

 30 

 2-8 

 2-6 

 2-4 

 2-2 

 20 

 1-8 

 1-6 

 1-4 

 1-2 

 10 

 OS 



























































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 / 



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-f 















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 r 

















































i n nr tv v vr vir i n ' m ur i inc 



JLumJbar Several Coccygeal 



Chart XVI. — Curves showing the Relative Values of the Ratios — 

 Dorsal Horns Ventral Horns 



31 



3-2 

 3 

 2-8 

 2-6 

 2-4 



2- 2 

 20 



3- 8 

 1-6 

 1-4 

 1-2 

 10 

 0-8 



Area of Cross-section of Cord ' Area of Cross-section of Cord 

 (D, broken line and cross). (V, line, dot, and cross). 



(Table XVII.) 



The ratio in the first lumbar region (see Table XVI) is in each case taken as unity. 

 The abscissa- 1 denote spinal nerve regions, the ordinates relative value at corresponding 

 regions. 



