CAUSE OF STRIATION OF VOLUNTARY MUSCULAR TISSUE. 319 
and examined with a power of from twenty to fifty diameters, 
when cross shadings are to be observed. ‘These are seen, more- 
over, to correspond with the surface impressions, and not only 
so, but they are reversed on altering the focus. Hensen’s stripe 
is generally very well seen. The most beautiful and convincing 
object to study in this connection is a scale of the Lepisma. 
They are oval in shape, transparent, and single refractile through- 
out, and beautifully ribbed in their length, these ribbings or 
groovings being indeed so fine that a power of at least 500 
diameters will be required to make out those points to be here 
described. You would think on looking at one of these scales 
that a piece of muscle was flattened out before you on the field : 
no rough balsam model, but a perfect illustration taken from 
the back of a tiny insect. 
The appearances it is needless to describe, for they are, almost 
to the minutest detail, those of a muscular fibre. The bright 
and dark stripe interchanging with every alteration of focus, 
Hensen’s stripe, and Dobie’s line (Krause’s membrane) are all to 
be seen. In the case of the Lepisma scale the line of Dobie 
is in the centre of a bright band, which is broader than the 
dark band with Hensen’s stripe. This is, of course, the other 
way in the case of the muscular fibre. 
We sce, therefore, that a muscular fibre presents just those 
Fic. 5.—Muscular fibre described by Messrs. Geddes and Beddard. 
Fic. 6.—On the right a nucleus is moulded on the fibre and is striped, the 
stripes corresponding to the depressions on its surface. 
Fie. 7.—This shows the muscular fibres of the heart. 
appearances which a transparent body of uniform texture and of 
similar shape would possess. However conclusive these proofs 
