270 



MUSCLE-TISSUE. 



S2 



Briicke has stated, the arrangement of the sarcous elements in 

 the live muscle-fiber greatly varies ; the reasons for this are not 

 yet clearly understood. Nevertheless, the schema of the struct- 

 ure of muscle-fiber was established by Heiisen under conditions 

 when the rows of sarcous elements were divided by a single 

 transverse light line, and Merkel divided this line into two. A. 

 Schafer adopted the schema of two narrow rows between two 

 broad ones. All these conditions are sometimes met with, but 

 they are not by any means the only, or the most common, ones. 

 The theories of Krause's muscle-caskets, and Schafer's connect- 

 ing lines, between the two narrow distal row's, have arisen from 

 the erroneous idea that the filaments run between the sareous 

 elements, while in reality they directly connect them, often at 



their edges. Not infrequently 

 -SI t ne sarcous elements, under the 

 microscope, appear in oblique 

 position, owing to the general 

 die shape of the muscle- 

 fiber, and a dark line is seen on 

 one end of the sarcous element, 

 which is a shortened view of its 

 breadth. This dark line, also, 

 had led observers to wrong con- 

 clusions. 



Chloride of gold is a good 

 re-agent for bringing to view 

 with great distinctness all the 

 above-described features. That 



114. STRIPED MUSCLE OF THE the narrow rows themselves are 

 WATER-BEETLE (HYDROPHILUS Pi- composed of small, sarcous ele- 

 CEUS). STAINED WITH CHLORIDE OF ments is shown in Fig. 114. 



This condition is exceptional, 

 , row of large, and s* row of smaii, sar- and still more so is the appear- 



cous elements, the latter stained deeper violet -, , , 



than the former. All rows interconnected by 81106 OI double narrow TOWS, 



delicate filaments. Between the rows an un- comnared With thp armPflrflnop 

 colored liquid. Magnified 1200 diameters. 



illustrated in Fig. 41, page 128. 



That in one muscle-fiber different arrangements of the sarcous 

 elements may occur, can be seen in the muscle of craw-fish. 

 Often in the fresh muscle the regular rows disappear, and a 

 uniform granulation is for a moment visible, while in the next 

 moment the rows are reestablished. In aU these conditions the 

 muscle-fiber executes contractions. (See Fig. 115.) 



