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

 iEir^vTrTTii n ur tv i i in 



I I IT T tl W I I I W I HUT 

 Znm-bctr Sacral CvccyqeaZ 



Chart XV. — Curve showing the Eatio of the Ventral Horns (V, line, dot, and cross) to 



the Dorsal Horns (D). 



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

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

 corresponding regions. 



The ratio v ^ n ^ ra | horns (V) j ncreaseg f rom fa e g rs t ^ the fourth lumbar 

 dorsal horns (JJ) 



region, and is approximately the same in the fourth and fifth. 



From the fifth lumbar region downwards to the end of the cord the ratio 

 decreases, being as 1 : 1 in the first coccygeal region. 



The ratio increases very rapidly in both the third and fourth lumbar 

 regions. It decreases very rapidly in the sixth and seventh lumbar and first 

 sacral regions, and more especially in the seventh lumbar. 



The ratio v ^ n ^ ra j- horns (V) ^ Q ^ n „ approximately the same in the second 

 dorsal horns (D) ° * e J 



sacral and first lumbar regions, the decrease between the fifth lumbar and 



second sacral region is seen to be less rapid than the corresponding increase 



between ihe first and fifth lumbar regions. 



B4. Ratio of the Dorsal and of the Ventral Horns of the Grey Substance to 

 the Total Area of the Cross-section of the Cord. 



Since the percentage of grey substance to the cross-section of the cord and 



the ratio v ^ n ^ ra | ^horns naye a i rea( jy been represented graphically in 



Charts III (G) and XV, no curves accompany the following table (XVI) giving 

 dorsal horns ventral horns 



the ratios 



total area of cross-section ' total area of cross-section 



