HISTOLOGY OF THE STRIPED MUSCLE-FIBRE. 
385 
appears during life — that is, there is no differentiation into 
sarcous elements, but transverse rows of dots, and longitudinal 
lines are alone seen, as in the living fibre. Fixed waves of 
contraction may also be found. 
Fig. 21 represents a portion of a fibre of Dytiscus stained in 
hsematoxylin after the action of spirit. It shows an alter- 
nation of bright and dim discs, the dim discs stained a deep 
purple and made up of a series of sarcous elements side by 
side. Across the middle of the bright discs a dotted or 
granular transverse line is seen. Fine longitudinal lines, the 
longitudinal bars of the network, may occasionally be seen 
crossing the bright discs. 
This account agrees for the most part with that given by 
Klein 1 as to the structure of muscle. He, however, figures a 
continuous line — the homogeneous Krause’s membrane — in 
the middle of the bright stripe, and no longitudinal fibrillation 
in the bright disc. 
Let us consider the influence of the intracellular network in 
producing the appearances known as sarcous elements, and 
Cohnheim’s areas, in the muscle-fibre. 
The matrix, or substance which lies in the interstices of the 
network, is of far greater bulk than the network. It is homo- 
geneous throughout ; nevertheless, it may be looked upon as 
being partially divided into columns or fibrils by the longi- 
tudinal bars of the network, and partially into discs — the con- 
tents of muscle compartments — by the transverse networks 
By the action of spirit the matrix becomes split into fibrils. 
The reagent causes this “ sarcous substance ’’ to shrink (pos- 
sibly by abstraction of water), and the homogeneous mass now 
separates into fibrils along the lines of greatest weakness — that 
is, along the guide lines formed by the longitudinal bars of the 
network. These fibrils may again divide transversely at the 
horizontal networks, producing sarcous elements (diag. 8). 
Thus the appearance of sarcous elements is seen, as described 
by Klein, 2 to be a post-mortem phenomenon. In conse- 
1 ‘ Atlas of Histology,’ p. 77. 
2 Loc. cit., p. 76. 
