338 



scribed, mention was made of the motor endings in striated muscle 

 tissue of the rabbit. The conclusion reached admits of the following 

 brief summary: — 



At the place of ending of the motor fibres, the neurolemma be- 

 comes continuous with the sarcolemma. The neuraxis, after losing- 

 its medullary sheath, terminates under the sarcolemma in an end- 

 brush the configuration of which varies, in a localized area of sarco- 

 plasm — Doyere's elevation — in which are found a varying number 

 of muscle nuclei. Emphasis may here be given for considerations 

 which will appear later, to the fact that the termination of the motor 

 nerves in striated muscle tissue, is to be found under the sarcolemma 

 of the muscle fibres. The figures given in the article, to which allusion 

 has been made, confirm, we believe, these conclusions. In double- 

 stained sections — methylene blue and alum carmine — of the recti 

 muscle of the rabbit the following observations have been made on 

 the sensory nerves terminating therein. 



The medullated nerves, as they course along between the muscle 

 fibres, give off numerous side branches ; the majority of these are non- 

 medullated and terminate on the adjacent muscle fibres. These short 

 side branches leave the medullated fibre at the nodes of Ranvier. A 

 number of them may terminate successively on one muscle fibre, see 

 Fig. 2; or, again, a nerve-fibre as it courses along between two muscle 

 fibres may alternately send side branches to two contiguous muscle 

 fibres, see Fig. 1. 



I can confirm the observation of Retzius, that these side branches 

 are now and then medullated for a short distance. The mode of end- 

 ing of these lateral twigs varies greatly. The ending may consist of 

 single end-disc of round, oval or pear-shaped (not shown in the figures 

 given), or several such end-discs may be arranged in a row united by 

 a fine nerve fibril (a, of Fig. 1), or slightly more complex as shown 

 in &, of the same figure. The endings reproduced in Fig. 2, show a 

 branched ending and are more complex. Numerous other configur- 

 ations have been observed. They may all, however, be reduced to end- 

 ings consisting of relatively large end-discs, which often stain deeply 

 in methylene blue and are found along the course of a fine nerve fibre 

 or at the end of its branches. These observations corroborate in the 

 main those given by Retzius, as a comparison of the accompanying 

 figures with those given in Plate XVIII of his article will show. 



In these double-stained sections, I have never observed a group- 

 ing of the muscle nuclei about the ending under discussion, such as 

 may always be observed in the motor endings of the rabbit and other 



