TRANSVERSELY STRIATED MUSCLES. gl 



elongated cavity. 1 In discussions respecting these ulti- 

 mate elements of muscle, extremely difficult relations 

 are involved, and I for my own part must confess that, 

 however much I am inclined to admit the uni-cellular 

 nature of the primitive fasciculi, I am still too familiar 

 with the peculiar appearances in their interior not to be 

 obliged to allow that another 

 view may be advanced. For 

 the present, however, we 

 must bear in mind that we 

 have to do with a structure 

 in which an external mem- 

 branous sheath (sarcolem- 

 ma) and contents are to be 

 distinguished. In the latter, acetic acid causes nuclei 

 to show themselves, and, when they (the contents) are 

 in their natural condition, the peculiar transverse and 

 longitudinal striation may be recognised in them. This- 



Fig. 24. Muscular elements from the heart of a puerperal woman. A. Peculiar 

 spindle-shaped cells precisely like the fibre-cells of the pulp of the spleen, probably 

 belonging to the sarcolemma and set free in teasing out the preparation, a. Cres- 

 centically curved cell, somewhat flat at one end, viewed on its surface. b. A 

 similar one, seen in profile, with flat nucleus, c, d. Cells, the nuclei of which lie 

 in a hernial protrusion of the membrane, e. A similar cell, viewed on its sur- 

 face, with its nucleus, as it were, lying upon it. B. A primitive fasciculus, without 

 its sheath (sarcolemma), with distinct longitudinal fibrils and large, roundish nuclei, 

 of which one contains two nucleoli (incipient partition). C. A primitive fasciculus, 

 which has been teased asunder and slightly cleared up by acetic acid ; besides a 

 divided nucleus, fine, awl-shaped, nucleus-like bodies are seen imbedded between 

 the longitudinal fibrils. 300 diameters. 



1 This cavity Leydig supposes to be lined by a membrane, and therefore really 

 to constitute a cell (connective-tissue corpuscle). The nuclei of every primitive 

 fasciculus would, therefore, according to this view, be the nuclei of connective- 

 tissue corpuscles, and the contractile substance, lying between these, would be 

 equivalent to the intercellular substance of ordinary connective tissue. The nuclei 

 here alluded to are the ordinary nuclei of muscle, as seen in the figs, quoted above 

 and must not be confounded with the awl-shaped bodies represented in fig. 24, f, 

 lying between the fibrils ; for, though these bodies look like nuclei, they are really, 

 according to Leydig, portions of the divided processes of some of hia connective- 

 tissue corpuscles. From a MS. note by the Author. 



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