HISTOLOGY OF THE STRIPED MUSCLE- FIBRE. 
387 
below by Krause’s membrane, and laterally by the boundaries 
of Cohnheim’s areas. Briicke 1 regards the isotropous lines 
which traverse the anisotropous disc as optical sections of 
the partitions between muskel-katschen. These partitions 
correspond with the longitudinal bars of the network and 
with Schafer’s rods. The alternation of bright and dim trans- 
verse bands has been looked upon by several observers as an 
optical effect, and not due to any anatomical differentiation 
here present. 
Heppner 2 and Strieker look upon the bright band as the 
expression of total reflexion, which occurs at the line of de- 
marcation between Krause’s membrane and the chief substance 
of the fibre. 
Bowman suggested that the transverse striping shown by the 
fibrillse was caused by their moniliform shape. Hay craft 8 has 
recently developed this view, and extended it to the whole 
fibre. 
Striped muscular fibres are met with in the animal kingdom, 
from the Ccelenterata upwards ; there is no reason to suppose 
that the cause of the transverse striation is different here from 
that in the insect. 
I have received the greatest sympathy during this investi- 
gation from my friend Mr. C. F. Marshall, with whom I 
have verified most of my results. The drawings of the net- 
work in the fibres of the Rat and Lobster are from gold pre- 
parations by him. Mr. Marshall is at present working on the 
histology of the muscle fibre, from the lowest types of the 
animal kingdom in which it occurs upwards, and has 'already 
obtained interesting results. A study of the comparative 
development or phylogeny of this network, and at the same 
time of its embryology, may lead to its undoubted recognition 
as an ordinary intracellular network. 
My thanks are also due to Prof. A. Milnes-Marshall, who 
1 ‘Quain’s Anat.,’ p. 127 ; and “Muskelf. im polarisirten Licht,” ‘Wiener 
Denkschr.,’ xv. 
2 * Strieker’s Handbook ’ (Syd. Socy.), p. 548, vol. iii. 
3 ‘Quart. Journ. Micro. Sci.,’ April, 1881. 
