ON THE STRUCTURE OF MUSCULAR FIBRE. 253 



acetic acid, the acid being in excess, and finally exposed to 

 bright sunlight, the outlines of long narrow cells and of 

 broad oblong cells were visible. (I subsequently succeeded 

 in isolating one of the broad cells in a fibre treated in the 

 ordinary way by gold solution and subsequent exposure to 

 light in acidulated water.) 



Ill gold preparations the end of a fibre had been sometimes 

 observed to be composed of a number of well-defined com- 

 partments, which when they shrunk towards the sarcolemma 

 after being acted on by chloride of gold, produced a central 

 canal of considerable dimensions. 



I had thus demonstrated in muscular fibre by the most 

 satisfactory of all methods, namely, isolation, the existence of 

 flat cells, of a network connected with central cellular pro- 

 toplasm, and of parallel rows of spindle elements. I had 

 obtained confirmatory evidence of the existence of the ap- 

 pearance known as Cohnheim's fields, and had produced arti- 

 ficially discs which corresponded to transverse sections of 

 Kolliker's muskel-sdulchen, and which also corresponded to 

 Cohnheim's fields. I had seen reason to believe in the 

 existence of the fibrilla as a separate entity and not 

 as the prodiiction of reagents. I could thus find evi- 

 dence of fibrillae, of cylindrical bands parallel to the long 

 axis of the fibre which I designated primary bundles (of 

 fibrillae) to mark their analogy with similar structures in 

 tendon and connective tissue, and of groups of these, which for 

 a similar reason I designated secondary bundles, the whole 

 forming the contents of the sarcolemma. Between the primary 

 bundles were rows of spindle elements and the existence of 

 a network corresponding in size and arrangement to Cohn- 

 heim's fields, justified the assumption that its meshes em- 

 braced the primary bundles. It was assumed from their 

 position in teased preparations that the flat cells were ap- 

 plied to the surfaces of the bundles. 



I have in the interval that has elapsed since the paper re- 

 ferred to was written obtained valuable confirmation of the 

 accuracy of my views. In June, 1874, whilst engaged in the 

 investigations already recorded, I treated fresh muscular fibrea 

 of the frog with logwood solution and glycerine in various 

 combinations. The fibres were sometimes rapidly stained 

 with a strong solution and then placed in glycerine; they 

 were sometimes placed immediately in glycerine, and log- 

 wood solution was drawn through the preparation by blotting- 

 paper suitably placed at the edge of the cover glass, the 

 excess being removed by fresh glycerine being drawn through 

 in a similar way. 



