164 THE TISSUES. 



tion of the structure of the motor nerve-ending is correct, there 

 would seem to be no reason why the sarcoplasm in which the telo- 

 dendria occur should be considered other than the sarcoplasm of 

 the muscle-fiber, the nuclei as muscle-nuclei ; the terms motor end- 

 plate, granular sole plate, and sole nuclei would therefore seem un- 

 necessary and misleading. It may be stated in this connection that 

 Bardeen has recently shown that in teased muscle-tissue subjected 

 to trypsin digestion the muscle substance may be removed from 

 the fiber leaving the sarcolemma and on its inner surface a por- 

 tion of the nerve -ending, with the neurolemma continuous with the 

 sarcolemma. He has also shown that the motor ending is in part 

 differentiated in connection with developing muscle-fibers before 

 a sarcolemma can be shown on such fibers. In figures 126 to 

 130 are shown motor nerve-endings from several vertebrates as 

 seen when stained with gold chlorid. 



The mass of sarcoplasm in which the neu raxes terminate as 

 above described is about 40 to 60 p long, 40 /abroad, and 6 to 10 /* 

 thick ; these dimensions vary greatly, however ; they may be greater 

 or less than the averages here given. 



In amphibia the motor nerve-endings are not so localized as 

 in the majority of vertebrates, as above described, but are spread 

 over a relatively greater surface of the muscle-fiber, and there is no 

 distinct accumulation of the sarcoplasm, and the muscle-nuclei are 



Fig. 125. Motor nerve-ending in voluntary muscle of rabbit, stained in methylene- 

 blue (intra vitam) (Huber, DeWitt, "Jour. Comp. Neurol.," vol. vn) : A, Surface 

 view ; B, longitudinal section through motor ending ; C, cross-section : a, a, a, neuraxes 

 of nerve-fibers ; s,s,s, sarcolemma ; /,/, neurilemma ; d, Doyere's elevation; mn, 

 muscle nuclei ; tn, telolemma nucleus. 



relatively less numerous. The telodendrion of the nerve-fiber is, 

 however, under the sarcolemma, between it and the contractile sub- 

 stance of the muscle-fiber. (Fig. 131.) 



Usually only one motor ending is found on each striated muscle- 

 fiber. This may be situated near the center of the muscle-fiber or 

 at a variable distance from the center, nearer one or the other of 

 its extremities. Now and then two nerve-endings are found on 

 one muscle-fiber, in which case the nerve-endings are found in close 

 proximity. 



