

MINUTE ANATOMY OF THE HEART. 249 



spaces within the muscular fibres* Varying conditions of 

 contraction of the musculature naturally produce variations in 

 the appearances presented. The fissures between the muscle 

 cells are filled, not only by the capillaries, but by a very deli- 

 cate connective tissue, which, in the form of a perimysium, 

 constitutes sheath-like investments, and appears to consist of 

 isolated branched cells. I have not been able to discover a 

 proper sarcolemma, i.e., a special delicate investing membrane 

 capable of isolation, around the muscle cells, and therefore, in 

 common with other observers, wholly deny the existence of 

 such a membrane investing the muscular fibres of the heart, 

 or, at least, maintain that, if present, it can be demonstrated 

 only with the greatest difficulty,^ Nevertheless the cells of 

 muscle, like all other naked cells, must possess a peripherical 

 investment. Independently of the above-mentioned element- 

 ary division into fibre cells, the muscular tissue of the heart 

 splits up into coarse subdivisions. By means of septa proceed- 

 ing from the perimysium, thick fasciculi or bundles are some- 

 times formed, which, as the well-known columnse carnese, are 

 particularly well marked in the auricles. In the walls of the 

 ventricles, on the other hand, the arrangement is rather of a 

 lamellar character, several thin expansions of muscle being so 

 applied to each other as to form a thicker plate, which is 

 visible even to the naked eye.J The thinner lamellae are either 

 connected with one another by extremely delicate connective 

 tissue, or there exists between them certain smooth-edged 



* Remak, loc. cit., Rindfieisch Lehrbuch der Pathologischen Gewebelehre, 

 1866, p. 73. Eberth, in accordance with this view, represents longitudinal 

 fissures as existing in the muscle cells ; but it maybe seen in his fig. 13, that 

 thsse really indicate the line of union of two adjacent cells. Moreover, Eberth 

 does not appear to attribute sufficient importance to my view of the natural 

 fissuring of the muscle ; at least, at p. 121, he observes that the muscular 

 network of the mammalian heart does not exist to the extent attributed to it ; 

 but that the appearances seen may frequently be produced by manipulation. 



+ As to Winkler, who maintains the presence of a sarcolemma in the 

 Archivfilr Anatomie und Physiologic for 1867, it is obvious from his ac- 

 count of the appearances presented on transverse section, that he really 

 treats of the sheaths of the perimysium. 



J See Henle, Handbuch der Systematische Anatomie, Band iii., Abth. 1 ; 

 Gefasselehre, p. 54, figs. 40 and 44. 



