120 



THE TISSUES 



cle discs (Fig. 62, /). What is known as the sarcous element of Bow- 

 man is that portion of a single fibrilla which is included in a single 

 disc, i.e.. between two adjacent lines of Krause (Fig. 62, b). 



The sarcoplasm is not evenly distributed throughout the fibre. 

 On cross section irregular trabeculae of sarcoplasm are seen extend- 

 ing in from the sarcolemma (Fig. 63). These separate the fibrillas 

 into bundles, the muscle columns of KolUkcr. A transverse section 





Fu, 



01. 



Fig. 62. 



X350- (Technic 4, 



Fig. 61. — Portion of Striated Voluntary Muscle Fibre. X350. VJ-Ccnnic 4, p. 

 129.) The fibre is seen to be marked transversely by alternate light and dark bands. 

 Through the centre of the light band is a deUcate dark line (Krause's line); through the 

 centre of the dark band a fine fight line indicates Hensen's line. The black line outlining 

 the fibre represents the sarcolemma. a, Fibrillse; b, muscle nucleus; c, Krause's line; 

 d, Hensen's line. 



Fig. 62. — Diagram of Structure of a Muscle Column of KoUiker. The appearance 

 presented by the cross-cut muscle column = Cohnheim's field, a, Muscle fibrillae; b, 

 sarcous element; c, Krause's fine; d, Hensen's fine; e, Cohnheim's field;/, muscle disc. 



of one of these columns presents the appearance of a- network of 

 sarcoplasm and of interfibrillar cement substance enclosing the 

 fibrillae. This appearance is known as CoJniheim^s field (Figs. 62 

 and 63).. 



Many of the details of structure of striated muscle have been determined by 

 studies upon the muscles of lower animals. These details are extremely com- 

 plicated and the numerous terms used to designate the same structure very con- 



