312 JOHN BERRY HAYCRAFT. 
very beautifully stained preparations of insects’ muscle, when 
using Boehmer’s solution of logwood. According to this observer, 
the dark stripes as well as Dobie’s lines are stained, while the 
rest of the fibre remains colourless. Klein, in his ‘ Atlas of 
Histology,’ figures the sarcous matter of the dark band clearly 
tinted, while that of the light stripe is absolutely colourless. 
The statement will not be far wrong, that every one at the pre- 
sent time considers the dark and light stripes as representing 
two different structures, distinct one from another in their phy- 
sical properties, for the dark stripe is spoken of as possessing a 
higher refracting power than the light, and chemically, for their 
compositions have already been hinted at by more than one ob- 
server. The dark stripes are looked upon by most as the true 
contracting part of the fibre, and they are termed the sarcous 
discs, or ‘ Muskelprismen,” “ Hauptsubstanz,” or masses of dis- 
diaclasts, and the light stripes as merely connecting matter (Zwis- 
chensubstanz), or “ Muskelkistchenfliissigkeit.”? Dobie’s line— 
more especially from the dipping down and attachment of the 
sarcolemma in insects’ muscle at this point—has been looked 
upon (Krause, ‘ Allgemeine und Microscopische Anatomie,’ sec- 
tion “ Muskel System,” pp. 80—90) as a delicate transverse mem- 
brane. ‘This view has received the assent of such microscopists 
as Klein and Ranvier, but not of Wagener (‘ Jahresberichte der 
Anatomie und Physiologie, Hofmann and Schwalbe) and 
Rutherford (‘Text-book of Physiology,’ p. 128), who describe 
Dobie’s line as consisting of a row of dots. Engelmann, indeed, 
describes a row of dots on either side of this line. 
Krause would have us believe that the fibre is divided by these 
membranes into a linear series of little boxes, each box or casket 
“Miiskelkistchen’’ containing a dark stripe with (as the membrane 
lies in the centre of the light stripe) one half of that on either 
side. Merkel (‘ Lehrbuch der Gewebelehre,’ Stuttgart, 1877, 
p- 83), to make the Miskelkastchen self-containing, affirms that 
the membrane of Krause is double. As to the stripe of Hensen, 
this is by very many looked upon as still another structure lying 
in the centre of the dark stripe ; it is in many fibres very clearly 
to be made out, its border being well defined, and in stained 
preparations (logwood) it has decidedly a lighter tint than the 
rest of the stripe. Still, some (Krause) look upon it as an in- 
dication of the highly refracting power of the dark stripe, com- 
paring the appearance with the light centre of an oil globule. 
The other cross strie, of which there are many described by 
some observers, but none at all universally accepted, are, as a 
rule, considered as indicating further complications in the muscle 
fibre ; indeed, the Miskelkistchen, by most advanced micro- 
scopists, although not +1, of an inch in length, consists of 
