Huber-DeWitt, Ncuro-tcndinons End-organs. 197 



each branching of the nerve fiber. Often numerous such end- 

 ings He close together and uniformly parallel to each other, the 

 whole resembling somewhat a poplar with its long, slender, 

 leafy, nearly parallel branches, or rather two such trees placed 

 base to base, with their tops extending toward the extremities 

 of the spindle. A not infrequent form of end-organ met in the 

 rabbit, has one or more large medullated nerves enter the organ 

 at the muscular extremity, extend unbranched through about 

 one-third the length of the organ and then break up suddenly 

 into numbers of these long, slender, densely packed, non-med- 

 ullated nerves. At times, mingled with the more characteristic 

 tufts, we see a single nerve rise from the medullated trunk, pass 

 out unbranched and terminate in a rather large, club-shaped 

 enlargement. In other spindles, we see endings more closely 

 resembling those in the cat, being shorter, wider and less com. 

 pact and spread out more over the surface of the tendon than 

 those we have described. The end-organ shown in Plate XVI, 

 Fig. 22, represents a rabbit's spindle in which three medullated 

 nerves enter the organ, each, after repeated subdivision, break- 

 ing up into the end-arborization, the final non-meduUated fibers, 

 with their lateral and terminal varicosities being shorter and 

 simpler than those found in many of the end-organs of the rab- 

 bit. But in all the end-organs studied, whatever their form, we 

 find the characteristic plate-like enlargements, besetting the 

 varicose fibers, larger and more complex and more closely 

 packed together than those in the cat, resembling more in com- 

 plexity and in the long, slender cylindrical plaques, the end- 

 organ of the dog. 



In the rat, the terminal tuft is comparatively simple. In 

 the triple end-organ, represented in Plate XVII, Fig. 23, we 

 have three large medullated nerves entering the organ, each di- 

 viding into two or three secondary branches, one of which 

 passes to one division of the organ and one to another, so that 

 there is a somewhat intricate intercrossing of nerves. The ter- 

 mination of each nerve is, however, comparatively simple, hav- 

 ing few side branches. The non-medullated fibers twine slightly 

 about and between the fascicuH and are beset with broad, irreg- 



