LIST OF MICROSCOPICAL SPECIMENS. 279 



No. of diameters 

 No. magnified. 



125. Distribution of nerve-fibres, with highly convoluted 



ramifications and bioplasts, constituting the ' end- 

 organs.' Muscle of white mouse . . . . 215 



126. Nerve-fibres with 'end-organs.' Muscular fibres 



of rat 700 



127. Ultimate distribution of fine pale nerve-fibres to 



voluntary muscle. Frog. In the centre of the 

 field is seen a branching muscular fibre, the fibres 

 resulting from the subdivision of the muscular 

 trunk, gradually taper into thin threads, which 

 are inserted into the connective tissue. Networks 

 of pale nerve-fibres are seen in all parts of the 

 preparation, but the muscular tissue has been 

 removed 220 



128. Ultimate distribution of finest nerves as networks 



and plexuses in the mylohyoid muscle of the hyla or 

 green tree frog. These fibres are very narrow, and 

 at the same time each is separated by a distinct 

 interval from its neighbours. See pi. VIII, fig. 1. 

 The state of things is, therefore, very favourable 

 for the observation of the * end-organs' if they are 

 present. I have never been able to discover one 

 in this beautiful example of voluntary muscle, 

 though I have found them in many other speci- 

 mens of muscle. Nerve-fibres may be traced for 

 an immense distance from the bundles of dark- 

 bordered fibres. Gradually they become less than 

 fc ne TO <A) o o f an i nen i n diameter, but still divide 

 and subdivide into fine threads with oval bio- 

 plasts or nuclei at. intervale, which, now running 

 parallel with the muscular fibre, then crossing it, 

 divide into branches, some of which after pursu- 

 ing a very long course may at last be traced to a 

 dark-bordered fibre in another part of the muscle. 

 I have succeeded in doing this in many different 

 specimens. The failure of others to obtain speci- 

 mens exhibiting the same appearances no doubt 

 depends upon a very different method of investi- 

 gation having been pursued. Anatomists for the 

 most part have not only failed to observe what I 

 have seen, but many have not yet succeeded in 

 demonstrating the fine pale nucleated fibres I de- 

 monstrated long ago in almost every tissue of the 

 frog 700 



