1862.] 71 



faint, and therefore somewhat difficult to recognize ; but with certain 

 reagents, such as acetic acid, they become darker, more granular, 

 and somewhat shrunken, with an irregular outline ; with others, such 

 as hydrochloric acid, they appear more homogeneous and pale. As 

 to their situation, they are attached along the fibres ; and I have 

 never seen them at the ends, as Kiihne in some instances found, 

 although sometimes they are placed very near the end. Sometimes 

 one is placed in the angle of division of a fibre. They appear to be 

 attached laterally; yet I cannot doubt that they lie within the 

 membranous sheath of the pale fibre, although the prolongation of 

 the latter over them cannot be shown as a separate structure. Were 

 further evidence required concerning the true nature of these 

 corpuscles, I might add that nuclei of precisely the same character 

 exist on the pale terminal fibres of the sensory nerves distributed to 

 muscles, as I shall more fully explain in the sequel, and indeed on 

 the final ramifications of nerves in general, of which we have examples 

 in the skin of the mouse and frog, in mucous membranes, in the 

 cornea, and in the electric organ of the torpedo. 



I come now to a more difficult question, namely, whether the pale 

 end-fibres of the nerves really lie within the muscular fibres or not. 

 Important as the determination of this question is in relation to 

 physiology, I can confidently say that I entered upon it without 

 bias, and studiously put aside every consideration which might 

 militate against the notion that the nerves penetrate into the muscular 

 fibres. Indeed I myself at one time thought that in certain parts of 

 the cutaneous pectoral muscle of the frog I had seen muscular fibres 

 penetrated by nerve-fibres. On careful investigation, however, I 

 became convinced that the seeming interior situation of the pale 

 fibres is an illusive appearance, and so many proofs against its reality 

 presented themselves, that I was finally constrained to come to a 

 different conclusion from Kiihne on this point also. 



According to my view, therefore, the pale terminal ramifications of 

 the nerves lie wholly without the muscular fibres, that is, on the outer 

 surface of the sarcolemma. In support of this opinion I may, without 

 insisting on negative evidence, which may be less regarded, adduce, in 

 the first place, the fact that not unfrequently a pale fibre may be seen 

 running on a muscular fibre towards the border, and then turning 

 round to the other side, obviously outside the sarcolemma. Again 



