CAUSE OF STRIATION OF VOLUNTARY MUSCULAR TIssuE. 815 
deed, the appearance has been often figured in the works, even 
of recent histologists. If the preparation be stained by any of 
the ordinary dyes, perhaps most readily by picro-carmine, the 
border is in all cases very distinct, and the regularly sinuous 
margin is unmistakable. Now, what is the significance of the 
wavy outline? It is, as will readily be understood, that the 
fibre is ampullated, the wavy outline being but the optical ex- 
pression of such a figure. A muscular fibre is, then, not a 
smooth cylinder, but is like the turned leg ofa chair, or like the 
transversely ribbed neck of a common water bottle in shape. If 
the fibre be broken up into fibrille, which is very easy, after 
maceration in alcohol, these are seen to have just the same cha- 
racters ; indeed, a small bundle of fibrils is most convenient for 
study. It may be well to remark that the ultimate fibrille often 
show but little cross marking, and appear almost filamentous ; 
that is, however, only due to their small size; a good lens will 
bring out both points. 
The above described appearances may be observed in all the 
varieties of muscle that I have as yet examined, e.g. those ob- 
tained from man, the dog, cat, rabbit, guinea-pig, mouse, frog, 
mussel, crab, bee, wasp, Dytiscus, Hydrophilus, common house- 
fly, &c., &c. 
The transverse stripings of the fibre are related to and cor- 
respond with the inequalities of the surface (Fig. 1). The little 
elevations at the borders correspond, of course, to the little ridges 
which run round the fibre, while the dips at the borders are the 
optical expressions of little valleys running between them. In 
the ordinary position the dark stripe marks the position of the 
ridge, and the light stripe lies in the little valleys, as will be seen 
on reference to fig. 1. ‘Then, again, Dobie’s line (Krause’s mem- 
brane), which is a faint dark band in the very centre of the bright 
stripe, runs along the bottom of the valleys (p in the diagram), and 
Hensen’s stripe in the centre of the dark band, lies on the exact 
summit of the ridges. (un, fig. 1.) 
This position of the stripes in a normal muscular fibre is the 
invariable rule, and the idea at once suggested itself, may not 
the shape of the fibre itself cause the cross stripings ? 
Any student of natural philosophy would at once affirm that 
a structureless fibre of such a shape must be cross striped, and a 
glance at the neck of the ribbed water bottle on the table will elicit 
the same answer from any one. 
The question we must now determine is, are the appearances 
seen in the fibre just the same in all their details, as would be 
produced by a piece of glass, or any other homogeneous trans- 
parent substance of the same shape? 
Before, however, entering into theoretical grounds, it may be 
