ON DISTRIBUTION OF THE CELLS IN THE INTERMEDIO-LATERAL TRACT. 125 



spires. There are 19 groups on the right and 18 on the left side. The maximum 

 number of cells in any single section is 78 (section 29 on the left side ; fig. 23). The 

 reticular group is increasing in importance and has frequently from 30 to 37 cells. The 

 distribution of the reticular group is along the hinder part of the outer margin of the 

 lateral horn, distinct from or continuous with the apical group, or it may extend 

 inwards as a wedge with its base towards the formatio reticularis. Its cells are fairly 

 large in size, and appear to be somewhat greater than those of the apical group. In the 

 lower fourth of the segment there is interpolated between the apical and the reticular 



C3L- 



Fig. 21 (D. 12, 172, L.).— The lateral horn is not pointed, but 

 forms a long, full, rounded projection. The intermedio- 

 latcral cells form a continuous group along the whole margin 

 of this swelling from the base of the anterior to that of the 

 posterior horn. Apical and reticular cells are inseparable. 



Fig. 22 (D. 12, 287, R.). — This figure shows an instance 

 where the reticular cells are present and the apical 

 series almost entirely wanting. 



group a very large third group of cells, containing in some sections 30 cells. This 

 group rapidly reaches a maximum, lasts for some 10 sections, and then rapidly disappears. 

 It is present only on the left side, and the size of the cells is not essentially different 

 from that of the other groups. The reticular group lies on a level with Clarke's column 

 (fig. 24). The apical group is distributed in the spike-like tip of the lateral horn. 

 Occasionally some of its cells pass along the anterior aspect ; more frequently they 

 stretch along the posterior border. There are occasional outlying cells in the white 

 matter. 



Second Lumbar Segment. — This segment was divided into 208 sections. The inter- 

 medio-lateral tract on the right side consists of 1464 cells and on the left of 1123. It 

 somewhat resembled C. 8 in the rapid diminution in the number of its cells. As far as 



