MUSCLE. 39 
iii, Ovoid cells: large oval cells with large nuclei: they 
are less numerous than the other two forms, and 
occur most abnndantly a short way below the 
mouths of the glands: they are said to secrete 
the acid of the gastric juice. 
C. Muscle. 
In muscular tissue the component cells are much elongated 
and, in the higher forms, very greatly modified. Muscular 
tissue is of two kinds: (1) striated, or voluntary; of which all 
muscles that are under the control of the will consist: and (2) 
non-striated, or involuntary ; forming those muscles over whose 
contractions the will has no direct control. The muscular tissue 
of the heart, which though involuntary is striated, forms the 
chief exception to this rule. 
I, Striated, or voluntary muscle. 
a. Crab’s muscle, Tease in glycerine a small piece of crab’s 
muscle that has been hardened in alcohol ; cover, and 
examine with both low and high powers : note :-— 
i, The elongated fibres of which the muscle consists. 
Each fibre is a single cell, and is enclosed in a 
delicate sheath—the sarcolemma—which will be 
visible in but few cases ; it is most readily seen at 
places where the fibre has been torn across. 
ii. The alternate light and dark bands with which the 
muscle fibres are marked transversely, and from 
which the name striated muscle is derived. 
iil. The readiness with which the fibres split up iongi- 
tudinally into fibrils, 
b. Frog’s muscle. Zease gently apiece of fresh frog’s muscle 
m normal salt solution, cover, and examine with high 
power: note 
i. The transverse striations. 
ii, The sarcolemma: best seen by slightly crushing 
the specimen. 
iii, The nuclei in the fibres: seen on addition of 
acetic acid. 
