282 SPECIAL HISTOLOGY. 



minute particles (" sarcous elements," Bowman) ; their sarco- 

 lemma is very delicate, or even wholly inappreciable ; and in 

 the fibres, there almost uniformly occur minute fatty granules, 

 which, with the nucleus, are frequently disposed in a series in 

 the axis of the fibre, and, where the muscular tissue is dege- 

 nerated, appear most usually to be excessively multiplied, 

 and also coloured. Much more, however, than by these cha- 

 racters, is the muscular tissue of the heart distinguished by the 

 intimate union of its elements, which, except on the internal 

 surface of the organ, not only never form manifestly distinct 

 bundles, being everywhere in close apposition with each other, 

 and separated only by a scanty connective tissue, but, as was 

 discovered by Leeuwenhoek, 1 and I also have found (vid. p. 94, 

 Fiff 275 v °l* *)* are directly united together in their 

 elements. These anastomoses of the muscular 

 fibres, which are a universal attribute of the 

 cardiac muscular tissue, are effected in the 

 human and mammalian heart generally, chiefly 

 by short, oblique, or transverse, usually small 

 fasciculi, and are extremely numerous, so that, 

 in many places in the ventricles and auricles 

 (whether universally I know not), numerous in- 

 stances of them are presented in every minute 

 portion. Besides these, there also exist true divi- 

 sions or fibres, by which the thickness of separate portions of 

 muscle may be rendered more considerable than it was ori- 

 ginally. 



The course of the muscular fibres of the heart is extremely 

 complex, and a general outline only of it can here be given. 

 The muscular structures of the ventricles and of the auricles 

 are completely distinct from each other; both, however, have 

 as their chief point of origin the ostia venosa of the ventricles, 

 where tough, tendinous tracts — the so-called annuli fibro- 

 cartilaginei — are situated, two anterior, on the right and left 

 of the aortal opening, and one posterior, which runs backwards 

 also from the aorta to the border of the auriculo-ventricular 

 septum, where it splits into two slender crura. In the auricles 

 are found : 1. fibres, which are common to both, in the form 

 Fig. 275. Anastomosing primitive fasciculus from the human heart. 

 ' [See note, p. 94, Vol. I.— Eds.] 



