SECT. 30.] 



MUSCULAR TISSUE. 



67 



Fig. 25. 



ranged in a linear series, and thereby producing the transversely 

 striated character of the muscular fibre ; 

 or they appear smooth, and then the fibres 

 or primitive bundles appear striated longi- 

 tudinally. Besides these fibrils, the mus- 

 cular fibres contain nothing but a small 

 quantity of a viscid substance uniting 

 them, and a certain number of roundish 

 or elongated cell-nuclei, which generally 

 lie upon the inner surface of the sarco- 

 lemma. The union of the muscular fibres 

 to form muscles and muscular coats, is 

 effected either by their being arranged 

 parallel to each other, or by their connec- 

 tion in form of true networks. Moreover, 

 they are enclosed by an envelope, of greater 

 or less firmness, named the perimysium, 

 which consists of connective tissue always 

 containing fine elastic fibres, and some- 

 times fat-cells ; and they are encircled by 



numerous blood-vessels and nerves. Two human muscular fibres; mag- 



nified 350 times. In the one tlio 



In chemical characters, the chief sub- bundle of floriii»(j.) is torn, ana the 



sarcolemma (a.) seen as an empty 



stance of the transversely striped muscular tube. 



fibres entirely agrees with the syntonin, men- 

 tioned in the preceding section. The sarco- 

 lemma strongly resists the action of alkalies 

 and acids, while the nuclei present the ordinary 

 characters of these structures. A fluid of an 

 acid reaction can be pressed out of the muscles, 

 in which Liebiy and Scherer have discovered an 

 interesting series of non-nitrogenous and nitro- 

 genous products of decomposition of the mus- 

 cular tissue. 



The transversely striated muscles are, in a high 

 degree, capable of contracting ; and, by reason 

 of their length, of bringing about very con- 

 siderable total effects. Their elements arise by 

 the transformation of single cells into long 

 fibres with many nuclei ; in some cases, also, 

 by coalescence of stellate cells. In the fully- 

 developed condition of these muscles, the nu- 

 tritive process is very active, as is evident from 

 f 2 



Fig. 26. 



Primitive fibrils, from a 



primitive bundle of 8 redon 



a. A small 



bundle; A. an isolated fibril. 



Magnified r.oo times. 



