74 C. F. MARSHALL. 



Dr. Gr. Thin* appears to be the first observer who described an 

 intracellular network in the fibre of striped muscle. He examined 

 frog's muscle treated with gold chloride in the following manner. 

 After staining with gold chloride the muscle was exposed to light in 

 acidulated water and then kept in strong acetic acid, at a temperature 

 of 38°C, from 6 — 24 hours. By this method he demonstrated a net- 

 work of fine fibres, concerning which he says, " this network was 

 composed of exceedingly fine fibres, and its meshes accurately 

 corresponded to Cohnheim's areas " (p. 252). He states that he 

 demonstrated in the muscle-fibre, by the process of isolation, (1) the 

 existence of flat cells (the muscle-corpuscles), (2) a network con- 

 nected with central cellular protoplasm, and (3) parallel rows of 

 spindle elements. Further on he states that he was " compelled to 

 associate the transverse markings with the existence of this network, 

 without attempting to explain the connection between them more 

 definitely" (p. 258). 



G-erlachf has written two papers on this subject. In the first 

 paper he states that the contractile contents of the sarcolemma are 

 traversed by a retiform substance continuous with, and identical 

 with the axis cylinder of the nerve. He thus regards the network 

 as of a nervous nature. 



In the second paper he states that an intravaginal nerve net- 

 work is present within the sarcolemma ; and that in gold specimens 

 striae are seen which behave in a manner similar to the intra- 

 vaginal network, and can be traced into continuity with it. He 

 divides muscle into an anisotropous contractile matrix, and an 

 isotropous nerve network. His results were obtained by the fol- 

 lowing method : The gold preparations were left several days in a 

 mixture of 1 — 2 parts hydrochloric acid, 20 parts glycerine, and 20 

 parts water. This method brought out the longitudinal striae. On 

 making gold preparations as above, and subsequently treating with 

 1 per cent, potassium cyanide, he states that the sarcolemma gives 

 way and the contents escape, partly as fine particles and partly in 



* " On the Structure of Muscular Fibre," " Quart. Journ. Micr. Sci.," vol. xvi. 

 (N. S.), 1876, pp. 251—259. 



t " Das Verhaltniss der Nerven zu den Muskeln der Wirbelthiere," Leipzig (Vogel), 

 1874. " Ueber das Verhaltniss der nervosen und contractilen Substanz des querge. 

 Streiften Muskels," "Arch, f. Mik. Anat.," Bd. xiii., 1887, p. 399. 



