20 H. E. JORDAN 
dise. This phenomenon of stratification may readily be demon- 
strated under favorable conditions in insect leg muscle. I have 
also convinced myself by micropolariscopic studies that the 
anisotropic stratum does not in general change its original more 
or less definite segregation approximately within the limits of 
the dark dise, at least in no regular and uniform manner, during 
contraction. But similar studies of contracted fibers show also 
that the anisotropy of the fiber and sarcostyle in this condition 
is relatively feeble. 
Figure 6, taken from Schaefer,?* is of prime importance because 
upon it are based diagrams (fig. 9) which are used in most of the 
current text-books of gross and microscopic anatomy to explain 
the mechanism of muscle contraction. This figure includes 
three sarcostyles of the wing muscle of the wasp, treated according 
to Rollet’s gold-chlorid technic. Sarcostyle C is said to be 
uncontracted; B, stretched, and A, contracted. It becomes 
necessary to recall the steps in Rollet’s technic. This technic 
involves fixation in 90 per cent alcohol for twenty-four hours, 
transference to strong glycerin for several hours, thorough 
washing in water, immersion in a 1 per cent gold-chlorid solution 
for from fifteen to thirty minutes, and final transference to a 
solution of one part of formic acid to three parts of water for 
twenty-four hours or longer. It is important to note that this 
technic involves the prolonged use of an acidulated hypotonic 
solution. 
Anticipating in part what will be more fully developed below, 
the following statements seem desirable here regarding this 
figure: In fiber C Schaefer lays stress upon, and attaches great 
importance to, the small circles in the upper end of the fiber. 
These he interprets as openings into pores in the dark disc. He 
assumes that these ‘pores’ are open towards the ‘hyaline sub- 
stance,’ closed within the dark ‘sarcous element.’ But such 
pores cannot be seen in fresh sarcostyles examined in Ringer’s 
solution; nor are they discernible in sarcostyles treated according 
to many other histologic methods. They must accordingly be 
interpreted as artifacts resulting from the use of Rollet’s technic. 
Moreover, granting that there actually occur capillary pores, 
