On the structure of cross-striated muscle. 197 



brane of Krause). Such disks, when seen edgewise have the appea- 

 rance shown in Fig - . 14; when seen on the Hat they present the 

 aspect shown in Figs. 15 or 16. The most striking point about the 

 view on the flat is that a well marked network, having either radial 

 or polygonal meshes, according to the source of the fibre which is 

 being investigated, is seen upon both surfaces: this fact can easily be 

 determined by focussing, and is universally admitted. To the con- 

 sideration of this network I shall have again to come back. But for 

 the present purpose the only point necessary to be determined is 

 whether a similar network is visible in every plane by focussing 

 through the whole thickness of the disk. 



It is much more difficult to determine this point satisfactorily 

 than might at first sight appear. For the strong networks of the 

 surfaces interfere with a clear view of the intermediate parts of the 

 disk, and tend to obscure any delicate net-like appearance winch might 

 there be exhibited. Rollett, who admits the difficulty, yet states that 

 lie has been able to make out the same pattern but with extreme 

 tineness of Lines, through every depth in these disks. Ramon y Cajal 1 ), 

 mi the other hand, denies that any tiling but fine dots, which he looks 

 upon as the optical sections of the longitudinal fibres of the reticulum, 

 can be seen between the surfaces. My own observations confirm the 

 fact that fine dots can be observed scattered over the optical section 

 of the intermediate part of the disk, but these dots are situated at 

 the nodes of a very delicate network, and this in every plane of the 

 disk except close to the surfaces, where the coarser, network is visible. 

 ( >ne network passes gradually into another as the focus is raised or 

 lowered, they must, therefore, be the optical effect of longitudinally 

 running septal planes and the transverse networks near the surfaces 

 ot the disks must be enlargements on these. 



The question, therefore, which has been propounded is answered 

 by all the methods in favour of the sarcostyle- and against the reticu- 

 lum-enchylema-theory. 



Although the answer which must, as I believe, be given to these 



l ) Op. cit. p. 210. 



