410 TRANSACTIONS OF THE CANADIAN INSTITUTE. [Vou. VIII. 
solution for three days, but usually a few hours sufficed to give forms 
showing typical distributions. 
When sufficiently acted upon by the reagent the muscle fibres 
were mounted directly on a slide in 50 per cent. glycerine, and placed in 
direct sunlight for several hours. Teased out thorax muscle fibre of 
insects which has been for four or five days in contact with a solution of 
the silver nitrate containing nitric acid, and then exposed to the 
sunlight, shews the fibrils marked by a transverse striation, similar to that 
obtained in the preparations demonstrating the distribution of the 
fat. The striae are granular, of a deep brown colour and they occur at 
regular intervals throughout the entire length of the fibre (Fig. 16). In 
addition to the deeply colored brown precipitate a diffuse reaction is 
frequently noticed in the light bands, perhaps in part due to a more 
rapid penetration of the nitric acid, and a consequent slight redistribu- 
tion of the chlorides. 
That the chlorides are not limited to the peripheral layers of the 
fibre, but extend in horizontal planes across it, may occasionally be 
observed in favourable preparations (Fig. 18). The granular character 
of the precipitate is distinctly recognizable, individual granules being 
readily discernible. On careful examination the division into dim and 
light bands is easily distinguished, and the chlorides are seen to be 
localized in the dim bands. At its upper and lower edges near the 
junction with the light bands. The reaction in this part of the fibril is 
very intense, and on prolonged treatment with silver nitrate a third 
striation frequently appears also in the dim band, but this is of a much 
fainter colour. This additional striation lies exactly in the centre of the 
band, marking the position of Hensen’s line (Fig. 17). 
Although the muscle tissue, unless in a finely divided condition, is 
very slowly penetrated by the reagent the reaction may occasionally be 
observed in a considerable number of contiguous fibres, which have not 
been separated and in these cases the strize appear as discs extending 
horizontally across several fibres (Fig. 19). 
The distribution of the chlorides in the dim band, however, is more 
readily demonstrated in the wing muscles. . The whole fibre is marked 
by many longitudinal striae (Fig. 20) lying along definite straight lines 
and parallel to one another. At the first glance, it appears as if these 
regularly distributed, deep brown lines were continuous throughout the 
entire length of the fibre, but a careful examination reveals the fact 
GR et 
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