STRIATED MUSCLE TISSUE 



At about the same time Krause described a dark transverse 

 line which bisected the light disk. This line, the membrane of 

 Krause (Dobie's line), may be readily seen under ordinarily high 

 magnification. The interpretation of this appearance, however, 

 is somewhat doubtful. Following its description by Amici in 

 1859 and Krause in 1868, it was considered that a complete mem- 

 brane bisected the light disk, but this conclusion was discredited 

 by the observations of Dobie, 

 Kuhne, and others, and is 

 strenuously opposed by Scha- 

 fer, who regards Krause's 

 membrane as the optical ex- 

 pression of a row of dark dots 

 or granules disposed in one 

 transverse plane, each dot ly- 

 ing in the angle between adja- 

 cent areas of un differentiated 

 sarcoplasm. 



Striated muscle cells rarely 

 branch, yet in those locations 

 where its fibres are inserted 

 into the subcutaneous or sub- 

 mucous connective tissue, e. g., 

 the face, scrotum, tongue, etc., 

 branching fibres frequently 

 occur. 



Within the muscles the 

 individual cells are united by 

 a delicate connective tissue 

 endomysinm which penetrates 

 between the fibres and sup- 

 ports a liberal supply of capil- 

 lary vessels. The muscle fibres 

 are, however, unequally dis- 

 tributed within the muscle, 

 numbers of muscle cells being 

 united to form fibre bundles 



or fasciculi, which are surrounded by thicker membranes of con- 

 nective tissue, the perimysium. The fasciculi are in turn united 

 by bands of connective tissue derived from a firm fibrous mem- 

 brane, i\\j)fgimysium, which surrounds the entire muscle. 



FIG. 69. FIBRILS FROM THE WING MUSCLES 



OF A WASP. 



A, contracted; #, stretched; (7, uncon- 

 tracted. The alternate dark and light disks 

 are prominent ; the membrane of Krause in 

 the light disk, and the line of Hensen in the 

 dark disk are well shown. Very highly 

 magnified. (After Schafer.) 



3, J\\p&m 



