r structure.

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_Observation._ The pupil can examine a piece of boiled beef, or the
leg of a fowl, and see the structure of the fibres and tendons of a
muscle.

[Illustration: Fig. 36. 1, A representation of the direction and
arrangement of the fibres in a fusiform, or spindle-shaped muscle. 2, In
a radiated muscle. 3, In a penniform muscle. 4, In a bipenniform muscle.
_t_, _t_, The tendons of a muscle.]

152. Muscles present various modifications in the arrangement of their
fibres, as relates to their tendinous structure. Sometimes they are
completely longitudinal, and terminate, at each extremity, in a
tendon, the entire muscle being spindle-shaped. In other situations,
they are disposed like the rays of a fan, converging to a tendinous
point, and constituting a _ra'di-ate_ muscle. Again they are
_pen'ni-form_, converging, like the plumes of a pen, to one side of a
tendon, which runs the whole length of the muscle; or they are
_bi-pen'ni-form_, converging to both sides of the tendon.

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How are tendons or cords formed? What is the expansion of a tendon
called? How can the structure of muscles and their fibres be shown?
What does fig. 36 represent? 152. Give the different arrangements of
muscular fibres.

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153. In the description of a muscle, its attachments are expressed by
the terms "origin" and "insertion." The term _origin_ is generally
applied to the more fixed or central attachment, or to the point
toward which motion is directed; while _insertion_ is assigned to the
more movable point, or to that most distant from the centre. The
middle, fleshy portion is called the "belly," or "swell." The color of
a muscle is red in warm-blooded fish and animals; and each fibre is
supplied with arteries, veins, lymphatics, and both sensitive and
motor nervous filaments.

154. The FASCIA is of various extent and thickness, distributed
through the different regions of the body, for the purpose of
investing and protecting the softer and more delicate organs. An
instance is seen in the membrane which envelopes a leg of beef, and
which is observed on the edges of the slices when it is cut for
broiling. When freshly exposed, it is brilliant in appearance, tough,
and inelastic. In the limbs it forms distinct sheaths to all the
muscles.

155. This tendinous membrane assists the muscles in their action, by
keeping up a tonic pressure on their