General physiology; an outline of the science of life . egg-cell exert upon the STIMULI AND THEIR ACTIONS 435 freely-moving sperm-cell (Fig. 212). The fact, which must other-wise appear very wonderful, that among the innumerable swarm ofspermatozoa of the various marine animals every species findsthe proper ovum, is in a great majority of cases a direct resultof chemotaxis, and is explained very simply by the further factthat every species of spermatozoon is chemotactic to thespecific substances that characterise the ovum of the corres-ponding species. We have here an adaptive phenomenon of th
General physiology; an outline of the science of life . egg-cell exert upon the STIMULI AND THEIR ACTIONS 435 freely-moving sperm-cell (Fig. 212). The fact, which must other-wise appear very wonderful, that among the innumerable swarm ofspermatozoa of the various marine animals every species findsthe proper ovum, is in a great majority of cases a direct resultof chemotaxis, and is explained very simply by the further factthat every species of spermatozoon is chemotactic to thespecific substances that characterise the ovum of the corres-ponding species. We have here an adaptive phenomenon of thesimplest kind, which gives us anew an idea of how extraordinarilydeeply the phenomena of chemotaxis reach into life-relations. Pfeffers experiment was as follows: He filled a capillary tube,sealed at one end, with a solution of c. 005 per cent, malic acidand placed it in a drop that contained a great number of thespermatozoids of a fern; the malic acid gradually diffused fromthe opening of the tube into the drop, and thus became the source N^4l^>A.
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Keywords: ., bookcentury1800, bookdecade1890, bookidgen, booksubjectphysiology
