. The cyclopædia of anatomy and physiology. Anatomy; Physiology; Zoology. MUSCULAR MOTION. 523 ing of tlie material composing the fibre, as is shown by the general outline of the part, but especially by the appearances visible in its interior. The transverse stripes, both light and dark, become longer and thinner; in other words, the discs expand in circumference, flatten and approximate to one another; or to use another form of expression, the fibrillae become shorter and thicker, both in the par- ticles composing them and the material con- necting those particles (Jig. 301). Fig. Fragm
. The cyclopædia of anatomy and physiology. Anatomy; Physiology; Zoology. MUSCULAR MOTION. 523 ing of tlie material composing the fibre, as is shown by the general outline of the part, but especially by the appearances visible in its interior. The transverse stripes, both light and dark, become longer and thinner; in other words, the discs expand in circumference, flatten and approximate to one another; or to use another form of expression, the fibrillae become shorter and thicker, both in the par- ticles composing them and the material con- necting those particles (Jig. 301). Fig. Fragment of an elementary fibre (from the eel) partially contracted in water. Magnified 300 dittiii, a, uncoutractcd part. b, contracted part, along the border of which, at c, ct the sarcolemma is raised from the surface by the water that has been absorbed, that has thereby caused the contraction, and by it has been expelled from the contractile mass. These changes are always local, or partial, and it is most evident from the characters they constantly present, that they are not limited to any determinate regions, points, or segments, but occur indifferently wherever the exciting cause may chance to be exerted. Neither discs nor fibrillae appear to have the smallest share, as aggregatiotis of particles bearing those par- ticular forms, in producing the phenomena of contraction. A contraction is never bounded to a particular number of discs or fibrillas, and is never accurately limited by the interval between two discs. It constantly happens that at the edge of the contracted part several discs are only partially engaged in it. A contraction generally, when commencing at the broken end of a fibre, occupies its whole width there; but when it commences at the border of the fibre it may be confined to a portion of many discs. And, further, a contraction never occu- pies the whole length of a fibre or fibrilla at once. A contraction excited in an elementary fibre by the contact of a hai
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