CAUSE OF STRIATION OF VOLUNTARY MUSCULAR TISSUE, 311 
dark band, as with Briicke, being anisotropous. The most 
recent view is, then, that both the light and the dark stripes 
doubly refract light, but that there are bands which lie between 
them and which are singly refracting. With the appearance 
Fic. 1.—This represents diagramatically a fibre viewed with a very high 
power. The borders are wavy, and the cross stripes correspond with 
these irregularities. (D) marks the position of Dobie’s lines placed in 
the centres of the depressions seen at the border. (H) represents 
Hensen’s stripes or Dobie’s light stripes placed on the summits of the 
ridges in the centres of the dark bands. 
Fic. 2.—This shows the appearance of the fibre with crossed nicols. The 
shaded parts are seen on the slopes between the ridges and depressions. 
They are explained fully in the text. 
Fic. 3.—A fibre is represented as seen with three positions of the lens. 
In (A) the lens is elevated, and the depressions appear dark. In (c) 
the lens is fully depressed, when the stripes are reversed, the depres- 
sion being now light with Dobie’s line in the centre, and the crests 
dark with Dobie’s light stripe in the midst. In (B) the intermediate 
stage is seen. 
which would partially warrant such a conclusion, I can entirely 
agree, but I shall endeavour to show hereafter how this may 
most satisfactorily be explained. It will readily be seen how 
Briicke’s view, until quite recently accepted, would drive one 
to the conclusion that the light and dark stripes represent two 
different structures alternating in the length of the fibre, and 
this is corroborated by statements as to the action of staining 
agents on the tissues. 
Picric acid stains muscle very readily, but it is but faintly 
tinted by carmine, logwood, or eosine, although Ranvier, in his 
‘Traité Technique d’Histologie,’ states that he has obtained 
