Lest We Forget - Wireless Anatomy Commentary

its movement can be observed under the microscope. No one knows the cause of this motion. Within each cell is a specially dense bit of protoplasm called the nucleus. It seems to be the center of life and activity of the whole cell for if deprived of it, the cell cannot long continue to live. The cell is an organic unit of life's smallest and simplest pattern of living tissue.

The fibrils of the muscle-protoplasm constitute the contractile part of the muscle-fibre [fiber]. They are exceedingly fine, and extend the entire length of the muscle-fibre [fiber], and consist of a series of minute rod-shaped segments with attenuated ends (sarcous elements [sarcous disks]), united by shorter and much thinner thread-like bridges, on each of which there is found a small granule or globula [globule].

Free muscle endings seem to have vibratory possibility.

	[above] Branched, striated muscle-fiber from the tongue of a frog.
	[left] (A) Free ending. Fig. 90. - Muscle-fiber from one of the ocular muscles of a rabbit, showing its free end; X 175.

Investigations have shown that the development of muscle continues throughout the life of the individual. Muscular tissue is consequently to be regarded as in a perpetual stage of transition; the destruction and compensatory reproduction of its elements going on hand in hand.

	(A) Glassy layer. (B) Cortex of hair. (C) Medulla of hair. (D) Cuticle of inner root-sheath. (E) Henle's layer. (F) Fibrous-tissue sheath. Cross-section of human hair with its follicle; X about 300.
	(A) Basement membrane. (B) Nonstriated muscle-cell. (C) Gland-cell. Cross-section of tubule of coiled portion of sweat-gland from human axilla [underarm, armpit]. Fixation with sublimate; X 600.