Huber-DeWitt, Nciiro-tendinous End-organs. 179 



at each extremity such as may be seen in the central tuft of 

 Fig. I, Plate XIII. 



Sometimes a nerve fiber approaches an end-tuft from a di- 

 rection at right angles to its length ; but before reaching it, di- 

 vides into three or four branches, each of which ends in a typical 

 end-bush, but all so massed and mingled together as to pro- 

 duce a most complex picture. At other times, the main nerve, 

 as it nears its extremity, shows very short internodal segments, 

 and at each of the nodes, a short medullated nerve, branching 

 and rebranching and ending in a typical tuft, is given off, 

 the whole producing the effect of one very large ending, spread 

 out over a considerable space. In Plate XIII, Fig. 2, we have 

 represented such an ending, in which the main nerve divides 

 into seven or eight branches, each subdividing a number of 

 times, and each subdivision terminating in a tuft of varicose 

 fibrils and producing the tree-like ending seen in the figure, 

 with its large bushy spreading top. In Plate XIII, Fig. i, we 

 have represented a very large ending, arising from the terminal 

 branching of a large medullated fiber. This fiber first divides 

 into two branches, one of which soon redivides into two second- 

 ary branches, at right angles to the main stem, which soon end 

 in the tuft of varicose fibrils. The other primary branch ex- 

 tends for some distance before dividing into two secondary 

 branches, one of which divides into tertiary branches at right 

 angles to itself and all terminate in end tufts. One of the lat- 

 ter tufts passes back and meets the top of the tuft coming from 

 the first branch, forming the spindle like ending seen in the cen- 

 ter of the figure and previously described. We have found 

 endings of the most varied size and complexity, depending on 

 the number of branches given off at each division and entering 

 into the formation of the end-organ. It has not been unusual 

 to observe twelve to fifteen end-tufts of different size and shape, 

 formed by the division of a single nerve fiber. 



Longitudinal sections of the frog's tendon, as represented 

 in Plate XIII, Fig. 3, show that these end-brushes are found, 

 not in the zone of passage from muscle to tendon, but deeply 

 embedded in the tendon. They show also that these endings 



