Huber-DeWitt, Nerve- Endings in Muscles. 185 



(i) The ramified terminations of the axis-cylinder in the 

 motorial endings of striped muscle are the end-brushes of the 

 neuraxes of motor neurons, and are similar in structure to the 

 end-brushes of other cerebro-spinal fibers. 



(2) This end-brush [das Geweih, Kiihne) terminates in 

 the sarcoplasma, therefore under the sarcolemma of the muscle 

 fibers. At the place of ending of the nerve fibers, the sarco- 

 plasma may be accumulated in a circumscribed mass, forming 

 an elevation, more or less distinct, on the side of the muscle 

 fiber, as in reptilia, birds and mammalia, or spread out over a 

 proportionately greater area of the muscle fiber, as in am- 

 phibia. In the mass of sarcoplasma, the muscle nuclei (sole 

 nuclei of other writers) are relatively more numerous than in 

 other parts of the muscle fiber. 



(3) The neurolemma of the nerve fiber terminating in the 

 motorial ending becomes continuous with the sarcolemma at 

 the point of entrance of the said nerve fiber into the sarcoplasma. 

 Over the endings, sarcolemma or neurolemma nuclei — telo- 

 lemma nuclei — are seen. 



4. The neuraxis of the motor neuron loses its medullary 

 sheath before piercing the sarcolemma. 



Motor endings in cardiac mnscle. No attempt will here be 

 made to discuss the whole question of the innervation of the mam- 

 malian heart nor even to refer to the now extensive literature 

 dealing with the subject; for this, the interested reader may 

 consult the articles of Retzius and Berkley and especially the 

 very recent communication by Jacques who has reviewed the 

 literature very extensively. 



We wish here simply to refer to the ultimate ending of the 

 motor nerves on the heart muscle cells and to draw attention to a 

 method for staining them which we believe will give more satis- 

 factory results than the methods hitherto used. We refer here to 

 the method used in staining the nerve ending in voluntary muscle; 

 namely staining in methylene blue, fixing in ammonium molyb- 

 date, embedding in paraffin and sectioning, and further staining 

 such sections in alum carmine. In heart muscle, prepared after 



