. The physiology of the domestic animals; a text-book for veterinary and medical students and practitioners. Physiology, Comparative; Domestic animals. MECHANICAL MOVEMENTS IN CELLS. 75 The contractility of protoplasm may be manifested by either partial or total contractions, the latter tending to cause the protoplasm to assume a spherical shape. Partial contractions are much more common, and consist in contractions along certain circumferences of the mass of protoplasm, and thus lead to the production of irregularity in outline. Movements so produced are described as amoeboid movements from t
. The physiology of the domestic animals; a text-book for veterinary and medical students and practitioners. Physiology, Comparative; Domestic animals. MECHANICAL MOVEMENTS IN CELLS. 75 The contractility of protoplasm may be manifested by either partial or total contractions, the latter tending to cause the protoplasm to assume a spherical shape. Partial contractions are much more common, and consist in contractions along certain circumferences of the mass of protoplasm, and thus lead to the production of irregularity in outline. Movements so produced are described as amoeboid movements from the fact that they are best seen in the amosba. Amoeboid movements have already been described, and are exempli- fied in many of the cells of which the bodies of the higher animals are made up. Thus, the colorless blood-corpuscles, lymph-cells, and corneal corpuscles possess throughout their entire life the power of changing their form in a manner entirely similar to that possessed by the amoeba (Fig. 47).. Fig 47 _Am<eboid Movement in a Colorless Blood-Corpuscle of the Fkos. (Engelmann.) The temperature was gradually raised from a to m, and then gradually reduced. The most striking illustration of this form of protoplasmic move- ment, seen in adult animals, is exemplified in the motions of pigment- cells in the skin of the chameleon. As is well known, the chameleon is capable of changing the hue of its skin, and this is simply due to the varying degrees of contraction of the pigment-cells, which are situated below the epidermis. When these cells send out branching prolonga- tions to the exterior, the skin surface of the chameleon, from the larger amount of pigment exposed, will take on a dark hue. In the different stages of contraction of these pigment-cells the tint of the skin wdl vary according as the pigment-cells are seen through a thicker or thinner layer of yellowish or almost colorless epidermal Please note that these images are extracted from scanned page im
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