256 DR. G. THIN. 



To begin with, its individual existence is ])laced beyond the 

 reach of rational scepticism. The appearance it presents is 

 distinct. The breadth of all the bundles which have been 

 isolated is uniform, and corresponds to the breadth which is 

 indicated when they are in their natural position in the 

 larger bundles. The individual primary bundles can be easily 

 traced in the secondary bundles. They never join or become 

 confounded with each other. When isolated they were seen 

 to be unstained, but the remains of a shreddy film of mem- 

 branous substance stained by logwood was sometimes 

 adherent to their surface. The surface of the primary 

 bundle itself Avas even and unbroken. The action of the 

 dye is evidently much dependent on exposure to light, as 

 when the preparations after being laid aside for a week were 

 again examined, the substance of the bundles was in 

 some instances stained a faint blvie. This increased effect 

 of the dye on elements which had been spared when pro- 

 tected in the substance of the fibre makes the permanence of 

 the preparations doubtful. The breadth of the primary 

 bandies is slightly less than the diameter of a human red 

 blood-corpuscle. 



The more the bundles were disturbed by efforts to isolate 

 them the more they were stripped of the nuclei which are 

 applied to their surface; but in some of them the arrange- 

 ment of the nuclei can be well seen even after isolation. 

 The cells to which the nuclei belonged are in some instances 

 preserved. Figs. 6, 7, and 8 represent the primary bundles 

 and the nuclei adlierent to them. In fig. 8 two narrow cells 

 are seen entire. The mode of application of the cells is 

 indicated by the nucleus being observed to double round the 

 bundle.^ 



The nuclei are much better preserved than the cells, and 

 can be observed to be distinctly of several sizes which would 

 indicate cells of different size or form. Two distinct forms 

 of cells have been seen, namely, the narrow elongated cells 

 shown in fig. 8 and the cells shown in fig. 9 (a). 



The cells shown in fig. 9 (a) are broad, square cells, pre- 

 cisely similar in form and arrangement to the cells described 

 by Ranvier in tendon, with this difference — that they are 

 smaller than the tendon-cells are in the animals in which they 

 are usually studied. This resemblance to the tendon cells is 

 shown further in a striking manner by the position of the 

 nuclei. In the tendon-cells the nuclei are not in the centre 



' The fold thus produced on the surface of the nucleus (creie d'em- 

 priente of Kanvier) has been already described in the unbroken fibre by 

 Dr. Weber, of Paris. 



