A Manual of Physiology, and of the Principles of Disease

This historic book may have numerous typos and missing text. Purchasers can usually download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1864 edition. Excerpt: ...epithelium. Those of the tracheal cells are shown upon p. 152. Their motion is very remarkable when watched by the microscope; they wave usually towards orifices, and all bend at once, like corn when affected by the wind, sometimes they sweep round, like the feathering of an oar. A little powdered charcoal makes their movements more apparent. They move long after muscular motion has ceased; thus, the tracheal cilia of man have been seen to wave 7 days after death, and those of the oesophagus of the turtle 19 days, when the body was becoming putrid. Ciliary motion is best preserved by a uniform degree of moisture and temperature, and continues longest in blood--whereas bile checks it at once. It appears to be independent of muscular or nervous force, as it remains so long after their departure, and even upon one separated epithelial-cell; and electricity, prussic acid, or opium, do not affect it. Spermatozoa are regarded by some as cells with single cilia. The enlargement and contraction of the cell by osmose is probably the cause of the motion of the cilia; and such motions in plants as the folding of the leaves of the sensitive plant, the bending of the stamens of the barberry, and the closing of the venus's fly-trap, are believed to be analogous. Locomotion is a faculty possessed by nearly all animals, and there is nothing analogous among plants. In man, the organs concerned in this function are either active--as the muscles, under the command of the cerebro-spinal system--or passive, including the bones, with the ligaments which bind them together; the cartilages, which render their ends smooth and elastic; the synovial membranes, which obviate friction; and the areolar and adipose tissues, which connect, yet separate and pack all the...