NON-STRIATED MUSCULAR FIBRE. — NERVE. 



729 



Fig. 389. 



570. The 'smooth' or Non-striated form of Muscular fibre, 

 which is especially found in the walls of the Stomach, Intestines, 

 Bladder, and other similar parts, is composed of flattened bands 

 whose diameter is usually between 1 -2000th and l-3000th of an 

 inch ; and these bands are collected into fasciculi, which do not lie 

 parallel with each other, but cross and interlace. By macerating 

 a portion of such Muscular substance, however, in dilute Nitric 

 acid (about one part of ordinary acid to three parts of water) 

 for two or three days, it is found that the bands just mentioned 

 may be easily separated into 



elongated Fusiform Cells, not un- 

 like Woody Fibre in shape ; each 

 distinguished, for the most part, 

 by the presence of a long staff- 

 shaped Nucleus, brought into view 

 by the action of Acetic acid. These 

 cells, in which the distinction be- 

 tween cell- wall and cell-contents 

 can by no means be clearly seen, 

 are composed of a soft yellow sub- 

 stance often containing small pale 

 granules, and sometimes yellow 

 globules of fatty matter. In the 

 coats of the Blood-vessels are 

 found cells having the same gene- 

 ral characters, but shorter and 

 wider in form ; and although 

 some of these approach very 

 closely in their general appear- 

 ance to Epithelium -cells, yet they 

 seem to have quite a different 

 nature, being distinguished by. their elongated Nuclei, as well as 

 by their contractile endowments. 



571. Nerve-substance. — Wherever a distinct Nervous System can 

 be made-out, it is found to consist of two very different forms of tissue ; 

 namely, the Cellular, which are the essential components of the 

 Ganglionic centres, and the Fibrous, of which the connecting Trunks 

 consist. The typical form of the Nerve-Cells or 'ganglion-globules' 

 may be regarded as globular ; but they often present an extension 

 into one or more long processes, which give them a ' caudate ' or a 

 ' stellate' aspect. These processes have been traced into continuity, 

 in some instances, with the axis-cylinders of nerve-tubes (Fig. 390) ; 

 whilst in other cases they seem to inosculate with those of other 

 vesicles. The Cells, which do not seem to possess a definite cell- 

 wall, are for the most part composed of a finely-granular substance, 

 which extends into its prolongations ; and in the midst of this is 

 usually to be seen a large well-defined nucleus. They also generally 

 contain Pigment-granules, which give them a reddish or yellowish- 



Structure of Non-striated Mus- 

 cular Fibre : — a, portion of tissue 

 showing Fusiform Cells a, a, with 

 elongated Nuclei b, b ;— b, a single 

 cell isolated and more highly mag- 

 nified ; — c, a similar cell treated 

 with acetic acid. 



