OBSERVATIONS ON STRIPED AND UNSTRIRED MUSCLE. 77 



In some cases he states that the longitudinal bars of the network 

 ■were not straight but zigzag. From the descriptions and figures it 

 is very probable that this appearance was due to pressure, and is not 

 normal. 



Bremer* also describes a well-defined network in the striped 

 muscle-fibre, evidently identical with that described by Betzius. 

 He states that the longitudinal lines are true fibrils, and not part 

 of cylindrical sheaths, as Gerlach maintained. He further traces the 

 axis cylinder of the nerve into direct continuity with the muscle- 

 corpuscles. 



He considers the longitudinal striae of Gerlach to be identical 

 with the longitudinal bars of the network, and explains the irregular 

 dotted appearance, or " Sprenkelung," of Gerlach's longitudinal striae 

 as being due to imperfect staining. 



Bremer's results, though published subsequently to those of 

 Betzius, were obtained quite independently. 



B. Mellandf has recently investigated the structure of the striped 

 muscle-fibre, and has arrived independently at results agreeing very 

 closely with those of Betzius and Bremer. This close correspondence 

 between the accounts of these three observers affords satisfactory 

 evidence of the correctness of their observations. 



The points of difference between the networks described by 

 Melland and Betzius are slight, the chief one being that Melland 

 figures the transverse networks in Dytiscus with more polygonal 

 meshes, and furnished with nodal thickenings at the points of 

 junction with the longitudinal bars of the network. Betzius figures 

 these in Locusta, but in Dytiscus he describes the transverse net- 

 works as generally composed almost entirely of radial fibres with 

 very few transverse connections ; and in place of nodal dots he 

 describes several thickenings or nodes placed irregularly, and much 

 fewer in number than the nodal dots described by Melland. Melland 

 does not trace any connection between the network and the muscle- 

 corpuscles, nor with the nerve-endings. He shows how the optical 

 appearances of striped muscle are caused by the network. He con- 

 siders the network to be intimately connected with the sarcolemma, 



* "Arch, fur Mikr. Anat.," lid. xxii., 1883, pp. 318—356. 



t "A Simplified View of the Structure of the Striped Muscle-fibre," "Quart. 

 Journ. Mier. Sci.," July, 1885. 



