106 



GENERAL ANATOMY OF THE TISSUES. 



§27. Transversely Striated 3Iuscular Tissue. — The elements of this tis- 

 sue consist essentially of the so-called muscular fibres or primitive muscu- 

 lar bundles, each of which, 0-004-0-03 of a line thick, consists of fine 

 fibrils surrounded by a special homogeneous, delicate, elastic investment, 

 the sarcolemma : the fibrils are generally enlarged at regular intervals, 

 so that they appear to consist of a series of many portions, and give a 



transversely striated as- 

 ^'s-35. Fig. 36. pgg^ j-Q |.j^g muscular 



fibres, or they appear 

 more even, and then the 

 primitive bundles pre- 

 sent a longitudinal stria- 

 tion. Besides these 

 fibrils, the muscular 

 -i fibres contain nothing 

 but a small quantity of 

 viscid substance uniting 

 them, and a certain num- 

 ber of rounded or elon- 

 gated cell-nuclei, which 

 generally lie against 

 the inner surface of the 

 sarcolemma. The associ- 

 ation of the muscular 

 fibres into muscles and 

 muscular membranes occurs in such a manner that they either apply 

 themselves parallel to one another, or are united into true networks of 

 transversely striated muscles. They then receive an investment of more 

 delicate or firmer connective tissue, the so-called perimysium, with which 

 finer elastic fibres and also fat-cells are frequently mingled ; and are, 

 besides, surrounded by numerous blood-vessels and nerves. 



In chemical characters the principal substance of the transversely 

 striated muscular fibres agrees perfectly with the syntonin referred to in 

 the previous section. The sarcolemma is very resistant to acids and 

 alkalies, whilst the nuclei present the common characters of those organs. 

 A fluid with an acid reaction may be expressed from the muscles, in 

 which Liebig and Scherer have discovered an interesting series of non- 

 nitrogenous and nitrogenous products of the decomposition of the mus- 

 cular tissue. 



The transversely striated muscles are in a high degree contractile, and 



Fig. 35. — Two muscular fibres of man ; magnified 350 diam. In one the bundle of fibrils, 

 b, is torn, and the sarcolemma, a, is to be seen as a mere empty tube. 



Fig. 36. — Primitive fibrils from a primitive bundle of the Axolotl {Siredon pisciformis) • 

 a, a small bundle of them ; b, an isolated fibril, magnified GOO diam. 



