THE HISTOLOGY OP THE STRIPED MUSCLE FIBRE. 233 



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. 



IT. 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 clots 

 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 

 heematoxylin 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 the sarcolemma 

 at the edges, and appear to divide the fibre into compartments. If 

 the near edge of one of these discs be focussed it appears as a 

 transverse row of dots crossing the fibre, and in many fibres fine 

 longitudinal lines may be seen joining the dots of two adjacent discs. 



In some fibres the appearance of a double row of dots crossing the 

 fibre in the position of the transverse network is seen. This is repre- 

 sented in fig. 1 6. It is noticed in the preparations made with acetic 

 acid, that the double rows of dots are met with, as a rule, in those 

 fibres which have undergone least pressure. In fibres expanded by 

 pressure a single row of transverse dots is alone observed. 



Fig. 17 represents a fibre treated with acetic acid and afterwards 

 stained in watery solution of logwood. At the upper part of the fibre 

 the thin dotted transverse discs are not seen edgeways but partially 

 from below. Lower down in the fibre the discs are seen more nearly 

 edgeways, and appear in perspective view as narrow granular bands. 

 These granular bands appear crossed longitudinally, and more or less 

 broken up into short parallel longitudinal segments, by fine bright 



