380 
B. MELLAND. 
When muscle splits into fibrils the fibres of the transverse net- 
work rupture midway between the nodal points ; the longi- 
tudinal threads and dots remain often attached to the fibril of 
sarcous substance, and cause it to appear transversely striated. 
The muscular fibres of the crayfish show exactly the same 
network, the precise method of gold staining seems to make 
little difference. Isolated portions of network are seen pulled 
out of shape, and thus with polyhedral meshes as in fig. 7. 
At other points the network is seen still arranged in its typical 
manner as in fig. 8. 
(e) Rat. — Iu the Rat most of the fibres show the typical 
arrangement into transverse and longitudinal portions (fig. 9). 
The transverse network is most marked. In certain isolated 
portions the dots at each nodal point of the network are seen 
surrounded by bright haloes as already described. 
Such then is the effect of gold staining on the muscular 
fibre. Can this network be demonstrated in any other way ? 
Any method which fixes the fibre in that condition in which it 
is when living gives rise to appearances closely resembling 
those described. Acetic and osmic acids seem to act in this 
way. 
II. Acetic Acid Preparations. 
Muscular fibres from the leg of the bee were placed in dilute 
acetic 1 per cent, for from five to fifteen seconds, then into 
glycerine and mounted. 
On examination they are seen to present a transverse row of 
dots at each membrane of Krause and longitudinal connecting 
rods. The network, like the sarcolemma, seems to resist the 
action of acetic acid more than the matrix or sarcous substance. 
If the fibre be stained in hsematoxylin after the action of the 
acetic, the network becomes stained to a greater extent than 
the matrix, which remains relatively unstained. 
The fibre now presents the appearance seen in fig. 15. Thin 
granular deeply-stained discs are seen crossing the fibre in the 
position of each Krause’s membrane. They are attached to 
