General physiology; an outline of the science of life . reover, leucocytes appear chemotactic, not only toward themetabolic products of Bacteria, but also, as Buchner has found,toward the proteids of the bodies of the Bacteria themselves, and 432 GENERAL PHYSIOLOGY whole series of substances of non-bacterial origin. Thus, Buchnerfound that broth made of wheat flour and that made of pea flourpossess especially strong chemotactic power. Finally, Sicherer(96) has recently shown that under proper conditions the leucocytesof warm-blooded animals outside the body exhibit their chemo-tactic propertie
General physiology; an outline of the science of life . reover, leucocytes appear chemotactic, not only toward themetabolic products of Bacteria, but also, as Buchner has found,toward the proteids of the bodies of the Bacteria themselves, and 432 GENERAL PHYSIOLOGY whole series of substances of non-bacterial origin. Thus, Buchnerfound that broth made of wheat flour and that made of pea flourpossess especially strong chemotactic power. Finally, Sicherer(96) has recently shown that under proper conditions the leucocytesof warm-blooded animals outside the body exhibit their chemo-tactic properties toward very varied substances for a long time, asclearly as in the living body itself. The chemotaxis of leucocytes plays an important role in thedevelopment of many animals. This is made clear especially bythe beautiful investigations of Kowalevsky (87) upon the fly-larva changes into the complete fly—a metamor-phosis that takes place fairly rapidly—the organs of the larvalbody, such as the creeping muscles, become superfluous, and. Fig. 209.—Leucocytes destroying the muscles in the metamorphosis of the larva of the fly. Thegranular masses are leucocytes, the striped masses bits of muscle. (After Kowalevsky.) begin to degenerate. The substances formed at the beginning ofthis degeneration have a strong chemotactic action upon theleucocytes; the latter wander into the degenerating organs ingreat crowds, and as genuine phagocytes devour the disintegratingmasses, and thus accelerate their removal (Fig. 209). It is charac-teristic that the phagocytes manifest their activity only in insectsin which the metamorphosis takes place very rapidly; but that inothers, as in the moth, and in the degeneration of the tail of thetadpole, they have no share. Nevertheless, Metschnikoff was ableto demonstrate analogous phenomena in the development ofstar-fishes. Chemotaxis is wide-spread in the flagellate Bacteria,Infusoria,andswarm-spores. In Bacteria the phenomenon was first
Size: 1804px × 1384px
Photo credit: © The Reading Room / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1800, bookdecade1890, bookidgen, booksubjectphysiology
