120 



DR ALEXANDER BHUCE 



marked off from each other, but there is less difference between the maxima and the 

 minima. The average maximum number of cells is the lowest in the whole of the 

 intermedio-lateral tract, amounting generally to between 20 and 30 cells, the highest 

 recorded being 41. The minima are generally under 10. The groups are more 

 distinct on the right than on the left side, and there are 11 on the right and 13 or 14 

 on the left (see graph). The lateral horn has only a slight indication of a pointed apex. 

 When this is present it is generally on a level with Clarke's column. The reticular 

 group is similar to that found in D. 7, as its cells are scattered and badly marked off 

 from those on its inner aspect. It frequently extends backwards behind Clarke's 

 column (fig. 13 and fig. 14, D. 8, 112 and 370), and it contains a considerable number 

 of outlying cells in the formatio reticularis. There are a few outlying cells in the 

 neighbourhood of the apical group (fig. 13, D. 8, 112). The cells vary in size. 



CI-*rL 



c. L t 



Fig. 11 (D. 7, 137, L. ). — The reticular and apical cells are 

 loosely aggregated, not sharply bounded on the inner 

 side. The lateral horn is less prominent than at higher 

 levels. 



Fig. 12 (D. 7, 316, L.).— The lateral horn is now a mere 

 rounded prominence. There are large cells in apical and 

 reticular groups ; these are shown in the anterior part of 

 the apical group, and one in the reticular group. 



Some very large multi-polar cells are found in the apical group, and there is a tendency 

 to an admixture of small rounded with medium-sized cells in the reticular group. As 

 in D. 7, the vascularity of the apical group is remarkable, and the supply appears to 

 come mainly direct from the lateral periphery of the cord. 



Ninth Dorsal Segment. — This segment was divided into 568 sections. The 

 intermedio-lateral tract on the right side consists of 8987 and on the left of 9011 cells. 

 The graph is similar to that of D. 8, except in the lower third, where there is a slight 

 tendency on the right side to the reappearance of a spire-like arrangement. The cell 

 clusters are somewhat less distinct from each other than in D. 8, the minimum number of 

 cells in the intervals between them seldom falling below 10. The average maximum 

 number of cells in the clusters is about 40, the largest number being 56 on the right 

 side. On the left side the average maximum is about 30, and the largest number is 41. 

 There are 18 clusters on the right side, and on the left either 18 or 20. 



