Huber-DeWitt, Nerve-Endings in Muscles. 215 



part, with the axial sheath. The spindle-nerves remain med- 

 ullated until they are within the axial sheath, the internodal seg- 

 ments becoming shorter as the muscle-spindle is approached ; 

 but this is more especially noticeable after they have penetrated 

 the capsule. After losing the medullary sheath (within the axial 

 sheath), the non-medullated continuation of spindle-nerves un- 

 dergoes further subdivision, before the ultimate ending is 

 reached. The general course and structure of the spindle-nerves 

 may be seen in Fig. 39, a sketch of a compound muscle-spin- 

 dle from the intrinsic plantar muscles of a dog, stained in meth- 

 ylene blue and fixed in ammonium picrate, teased and cleared 

 in glycerine-ammonium-picrate. See also Fig. 38, a smaller 

 spindle, also from the dog, and prepared in the same way. 

 In both the figures, only the intrafusal fibers, with the 

 spindle-nerves and their endings are shown. Observations 

 on the ultimate ending of the non-medullated terminal 

 branches of the spindle-nerves have been made by Kerch- 

 ner (who mentions in his account observations on man, cat, 

 rabbit, rat, and mouse) and by Ruffini (man and cat) and 

 by KoUiker, who mentions briefly and diagrams the ending of 

 a spindle-nerve in the muscle-spindle of a rabbit. The observa- 

 tions of these investigators were made on tissues stained in gold 

 chloride, and, while we are not able to add materially to the ac- 

 counts which Kerschner and Ruffini have given, yet, as our ob- 

 servations were made on tissues stained in methylene blue, and, 

 to some extent (cat and rabbit) on tissues stained in methylene 

 blue, fixed, sectioned and double stained in alum carmine and 

 cochineal, we may here present our results as corroborative 

 evidence. 



Ruffini, whose account we may here follow (as the few fig- 

 ures he gives are the only ones with which we are familiar, 

 comparable to the ones given by us), describes for the cat, three 

 types of ultimate endings of the spindle-nerves — spiral, circular, 

 and flower-like endings (" terminaisons a spirales, a anneaux, 

 et a fleurs"). Of these, the spiral endings may be first consid- 

 ered, as they seem to us the most typical. The non-medullated 

 terminal branch of the spindle-nerve thus ending, i^attens out 



