232 SPECIAL HISTOLOGY. 



further than to the periosteum or perickondrium, terminating abruptly 

 on those membranes, with the fibres of which they are not, in any way, 

 continuous, nor do they come into immediate contact with the bone or 

 cartilage. Where the muscles extend to the skin, they either expand 

 immediately beneath, and without any connection with it, or radiate in 

 it, in the form of larger or smaller divergent fasciculi (facial muscles) ; 

 in which case they appear to be inserted, at all events occasionally, at 

 once into the filamentary processes of connective tissue.* But the pre- 

 cise mode of connection of these tissues has not yet been ascertained. 



80. The sinews, tendons, are brilliant, white or yellowish structures, 

 composed almost entirely of connective tissue. They are subdivided, 

 according to their figure, into the rounded, cord-like, true tendons, and 

 into membranous aponeuroses (centrum tendineum, galea, tendons of 

 the abdominal muscles, latissimus dorsi, cucullaris, &c.). The two 

 forms, either in their external configuration or internal constitution, do 

 not admit of definite distinction ; they consist of connective tissue, 

 which is characterized by the parallelism of its elementary fibres, its 

 consistence, and its poverty in elastic filaments. The elements of the 

 connective tissue, the fibrillce, may be readily perceived, in fresh tendon, 

 to be, as they are everywhere, extremely minute. In the cord-like 

 tendons, they are slightly wavy in their course, all perfectly uniform in 

 size, parallel to the long axis of the tendon, and in the recent state so 

 closely approximated, that the demonstration of the existence of primi- 

 tive fasciculi is not easy. Such fasciculi, however, do exist, having a 

 breadth of 0-006-0-008 of a line, and a rounded polygonal figure, as 

 may be seen, especially in transverse sections of dried tendons, particu- 

 larly on the addition of alkalies. But in the natural state they are so 

 firmly united that they cannot be isolated. 



On the other hand, in true tendons, in the recent state, secondary 

 and tertiary fasciculi are very evident (Fig. 95). Delicate dissepiments, 

 in fact, of loose connective tissue, penetrate the substance of the tendon, 



* [The insertion of muscles without the intermediation of tendons, directly into the con- 

 nective tissue of the skin and mucous membranes, is seen very beautifully in the tongue and 

 in the facial muscles of Mammals. The former case has been well-described by Dr. Salter 

 (Todd's " Cyclopaedia," article " Tongue") ; the latter may be examined with great ease in 

 the levator labii superioris of the Rat. Here the muscular bundles run in the subcutaneous 

 connective tissue, keeping a pretty even diameter until they nearly reach their insertions. 

 They then divide into many branches, each of which either tapers off to a conical extremity, 

 or divides into a number of delicate pointed processes. In either case, the ends of the mus- 

 cular fibre gradually or suddenly lose their striation, and pass directly into the irregular 

 nucleated bands of the connective tissue. No sarcolemma can be demonstrated in the 

 branched ends of the muscles, and the bands of the connective tissue are directly continuous 

 with the matrix of the muscle; the change, from the one to the other, being evidenced 

 merely by the appearance of the sarcous elements. Nothing can afford a more complete 

 proof of the homology between the pseudo-fibril lated tissue of muscle and that of connective 

 tissue, than what we find here. TBS.] 



