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



increases from the fourth to the first sacral region, a slight fall being noticed 

 in the seventh lumbar. The ratio decreases in the second, third, and fourth 

 sacral regions, but increases again through the coccygeal regions, the increase 

 being very marked in the third. 



Comparing the ratio of the two columns in different regions with that in 

 the first lumbar, it is seen that the ratio is T4 and 1*6 times as great in the 

 first sacral and second coccygeal regions respectively, and becomes 21 times 

 as great in the third coccygeal. 



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 Zu,m,bar ScLcraZ CoccyqeaZ 



Chart XII. — Curves showing the Ratio of the Ventro-lateral Columns (A, line and dot) 



to the Dorsal Columns (P). 

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

 plotted (Table XI). The abscissas denote spinal nerve regions, the ordinates the ratio at 

 the corresponding regions. 



Bl. Section Area of the Dorsal a.nd of the Ventral Horns of the Grey 

 Substance in the Region of each Spinal Nerve. 

 A remarkable difference is observable in the form of the two curves repre- 

 senting the section areas of the dorsal and the ventral horns of the grey 

 substance.* 



The curve indicating the dorsal horns (D) (Chart XIII) is comparatively 

 flat throughout the portion of the cord examined, whilst that denoting the 

 * For definition of terms " dorsal " and " ventral horns " see p. 90. 



