Huber-DeWitt, Nerve-Endings tn Muscles. 217 



the figure, no distinct spirals are here shown, the ending con- 

 sisting of broad, irregular main stems resting on the intrafusal 

 fiber, from which side branches are given off which partly or 

 completely encircle the intrafusal fibers. 



That the endings, as above described, are outside of the 

 sarcolemma of the intrafusal fibers may be seen in Figs. 34 and 

 35 ; they are, however, within the connective tissue layer sur- 

 rounding each intrafusal fiber. Spindle-nerves may end on more 

 than one intrafusal fiber, as is shown in Figs. 33, 38 and 39, and 

 especially well shown in Fig. 34, a sketch of a somewhat ob- 

 lique section of a large muscle-spindle of a cat. The large med- 

 uUated fiber shown in this figure divides into two non-medul- 

 lated branches, one of which may be traced to five relatively 

 small intrafusal fibers. 



It needs to be stated, however, that, while a spindle-nerve 

 may end on several intrafusal fibers (on an average 3 or 4), other 

 spindle-nerves going to the same area of nerve distribution, or 

 to other areas in the compound spindle, may and often do end 

 on the same intrafusal fibers. Figs. 38 and 39 may serve to 

 show this. In some of the larger muscle-spindles containing 

 12 to 15 intrafusal fibers, a number of spindle-nerves end 

 in one area of nerve distribution, surrounding three, four, or five 

 intrafusal fibers in one portion of the spindle, another small 

 bundle of spindle-nerves ending on another group of intrafusal 

 fibers in another portion of the spindle; the whole spindle being 

 surrounded by one capsule. 



We have not found opportunity to investigate the end- 

 ings of spindle-nerves in the muscle-spindles of man. That 

 these structures are present in man has been abundantly shown. 

 Investigators who have regarded them as pathological structures 

 have worked on human material, and the figures they give leave 

 no room for doubt as to the identity of the structures they 

 have described, with what has been described as muscle-spin- 

 dles in other vertebrates. Kerschner and Ruffini have studied 

 the nerve endings in muscle-spindles of man with the gold chlo- 

 ride method. They both state that the annulo-spiral endings 

 are not found here. The ending seems compact, and from what 



