194 THE TISSUE OF THE ORGANIC MUSCLES, BY J. AKNOLD. 



directions, transverse and oblique sections of the fibres and 

 nuclei appear (fig. 32, a and 6). The quantity of connecting sub- 

 stance is sometimes very sparing, so that the surfaces of the 

 fibres are in almost direct contact, or are separated only by very 

 thin layers or columns of the connecting substance. Occasion- 

 ally, however, it is more abundant. In the former case the 

 muscular fibres appear, on transverse section, as closely com- 

 pressed polygonal areas; in the latter, as roundish spaces, between 

 which are more or less broad laminae of the connecting sub- 

 stance. This material is homogeneous, except that it contains 

 numerous pale branched cells, the processes of which inter- 

 communicate, and also a moderate number of dark, highly 

 refractile granules, O'OOl to 0*002 millimeters in diameter, 

 which are always visible. They sometimes lie in the centre of 

 the connecting material, sometimes close to the borders of the 

 spindle-like expansion of the fibre cells. They closely resemble 

 the granules of the nucleus. In specimens treated with solu- 

 tions of chloride of gold they present a dark violet tint, and 

 are always much darker than other parts of the connecting 

 substance (fig. 32, c). 



Both the muscular fasciculi and the membranous expansions 

 are invested both externally and internally by connective tissue, 

 which, for the most part, is distinctly fibrillar, and contains 

 loose fibres of connective and elastic tissue. By means of 

 this the several laminae are united into a membrane, and the 

 fibres into fasciculi. The latter are sometimes so combined as 

 to form a tough, dense, flattened or roundish mass, which, as 

 Treitz* has shown, fulfils the office of a tendon. 



VESSELS. The layers of the connective tissue investing 

 the fasciculi and membranes of organic muscular tissue, are 

 traversed by numerous arteries of various size, which break up 

 into a network of capillaries, from which again the veins take 

 origin. These, like the arteries, run in the investing connective 

 tissue ; but the capillaries penetrate the muscular layers. The 

 meshes of the capillary plexus are of moderate width, and are 



Prager Vierteljahresschrift, Band i., 1852. 



