82 THE MICROSCOPE. 
The minute histology of striated muscle has not yet been deci- 
ded. The prevalent idea is this: The lighter strie represent a 
cement substance, the darker ones the muscle substance. With a 
high power these dark strize are seen to be divided by fine longitu- 
dinal lines. The substance between the longitudinal striz on the 
one side and the cross striz on the other is called a muscle-case. 
Within this case, which is bounded by an exceedingly delicate mem- 
brane, is a small, striated muscle body surrounded by an indif- 
ferent fluid. 
Harden a piece of muscle in alcohol, embed in paraffin and 
make transverse sections. Stain slightly with borax carmine and 
mount in balsam. The arrangement of the fibers can be studied. 
Between them is a small amount of delicate connective tissue——the 
perimysium. With a high power the fibers themselves are found to 
be traversed with a delicate network—the so-called areas or fields of 
Cohnheim. The lines represent the cement substance between the 
primitive fibrils. 
Non-Srriarep Muscre.—Fill the bladder of a good-sized frog 
with air, in order to define it, remove and place it in glycerin for two or 
three days. With arather stiff camel’s hair brush vigorously rub off the 
epithelium, stain in hematoxylin and mount in glycerin or balsam. 
Examine with a high power. Little bands of spindle-shaped cells 
constitute the muscle fibers. Hach cell is fusiform, occasionally 
possessing branched processes, nucleated, marked with longitudinal 
strie and about 1, inch in length. It is not inclosed by a mem- 
brane. A bundle of this form of muscle fiber is composed of large 
numbers of these spindle cells held together by a homogeneous 
cement substance. 
Heart Musciz.—Tease a portion of this muscle in the salt solu- 
tion, stain with a drop of eosin solution and examine. The fibers, much 
smaller than the voluntary variety, are striated transversely and lon- 
gitudinally ; are very short and branched, usually at one end ; con- 
tain a nucleus embedded in their substance ; possess no sarcolemma 
and are held together by a cement substance and small quantities 
of fibrillated tissue. 
Permanent preparations of muscle can be made according to 
directions given in the November number, in an excellent paper by 
V. A. Latham, and need not be repeated here. Learn to distinguish 
the various sorts of muscle, especially the non-striated variety, which 
so closely resembles certain connective tissues. 
