1908-9. | MICROCHEMISTRY OF STRIATED MUSCLE. A413 
To obviate the difficulty arising from this fact all the experiments here 
' detailed were carried out upon insect muscle, which is free from that 
compound or possesses it only in infinitesimal quantities. The 
reaction in the tissue is in all cases immediate, the maximum result 
being obtained in 3 to 5 minutes. Leaving the muscle fibres in contact 
with the reagent for a longer period of time in no case intensified or 
enhanced the results. 
The tissue must be fresh and thoroughly teased-out, and for this 
purpose glass points or quills were used. The teased-out material, 
without further treatment, was then placed in the cobalt solution for five 
to fifteen minutes, washed thoroughly in ice-cold water, and mounted on 
a slide in equal parts of glycerine and concentrated ammonium sulphide. 
The wing muscles of insects shew the distribution of this salt in a 
remarkable manner and throughout a marked resemblance is observed 
to the results obtained with the reagents for the chlorides and fats. 
~The potassium as in the case of the two above mentioned muscle 
constituents may be restricted to either the dim or to the light band, or 
it may occur simultaneously in both. When the dim band alone is 
affected a longitudinal striation is more or less clearly marked (Figs. 24- 
25) and this may possess a granular appearance extending continuously 
through the dim band (Fig. 25) or it may be limited to the two zones 
forming the upper and lower third of this band while the central third is 
comparatively free (Fig. 26). The striations when restricted to these 
latter situations, i.e, the upper and lower thirds of the dim band, do 
not possess a granular character, or if so, it is difficult to distinguish. 
In Fig. 24 a marked condensation of the potassium is evidenced 
along the extreme border line of the dim band, and also midway 
between these, along Hensen’s line. 
When the potassium is localized in the light band apparently, it 
“may occur in the longitudinal striation, an example of which is repre- 
sented in Fig. 28, or it may be irregularly disposed (Fig. 30) without 
any trace of striation. An approximation to the restriction of this 
inorganic material to the border of the light band is occasionally met 
with (Fig. 27) where, many of the striations are confined entirely to this 
part of the fibre. Such preparations afford conclusive evidence of the 
change in position of the inorganic constituents. That this redistri- 
bution is intimately connected with the activity of the muscle seems 
apparent from such fibres, as those represented in Fig. 31, where a wave 
of contraction is advancing upward over the muscle. In the lower part 
