214 MODE OF TERMINATION OF MOTOR NERVES, BY W. KUHNE." 



some places attains a considerable length, and, running along 

 the bulb, terminates at its pointed end in a small swelling. 

 This is all that has been ascertained up to the present time re- 

 specting the termination of the nerves in the Amphibia ; the 

 muscles of Tritons, Toads, the Proteus, and Salamanders present- 

 ing the same characters as those of the Frog. In these animals 

 none of the granular and nucleated matrix is to be found which 

 exists in the muscles of Arthropoda. A muscle nucleus with a 

 small amount of protoplasm around it may, indeed, lie near 

 the intra-muscular axis cylinder, but we never find at this point 

 any special or peculiar disposition of this portion of the mus- 

 cular contents. As regards the position of the terminal bulbs, 

 as from their form these structures are named, they appear 

 either to lie close to the nerves and on the same plane, or, as 

 in the majority of instances, upon the latter and between them 

 and the sarcolemma. Occasionally the author believes he has 

 observed them to be absent. No physiological or morpho- 

 logical explanation has been advanced in respect to the sig- 

 nificance of the nerve bulb ; but it appears highly probable 

 that the nuclei represent the earlier formative cells of the 

 nerve and muscle, and consequently may be compared in some 

 measure in their structure to the nuclei of the cells connected 

 with nerves in the cutis of the tadpole that have been de- 

 scribed by Hensen. According to this observer, the embryonic 

 nerve fibres terminate in the nucleoli of these nucleated cells ; 

 the small pear-shaped knob at the end of the central fibre in 

 the nerve bulbs would therefore correspond to the nucleoli. 



Although there can be thus no doubt that in the Amphibia the 

 nerve sheath is continuous with the sarcolemma, from whence 

 it obviously follows that the contents of the former, if it ex- 

 tend beyond this point, must lie beneath the sarcolemma ; yet 

 this doctrine has received much opposition. The accuracy of the 

 statements that have here been made may, however, be irrefra- 

 gably proved by careful inquiry. The whole contents of the 

 freshly isolated muscular fibre can be rendered fluid by hydro- 

 chloric acid of 1 per cent., whilst not only the primarily coagu- 

 lated muscle plasma, but also the greater part of the muscle 

 prisms, can be converted into a solution of syntonine. The 

 entire contents of the muscle then, as is well known, move 



