The cell in development and inheritance . their fertilizing power, and their movements may continuethroughout this period. In many cases they are motionless whenfirst discharged, and only begin their characteristic swimming move-ments after coming in contact with the water. There is clear evi- UNION OF THE GERM-CELLS 197 dence of a definite attraction between the germ-cells, which isin some cases so marked (for example in the polyp Renilla) thatwhen spermatozoa and ova are mixed in a small vessel, each ovumbecomes in a few moments surrounded by a dense fringe of sperma-tozoa attached to its pe
The cell in development and inheritance . their fertilizing power, and their movements may continuethroughout this period. In many cases they are motionless whenfirst discharged, and only begin their characteristic swimming move-ments after coming in contact with the water. There is clear evi- UNION OF THE GERM-CELLS 197 dence of a definite attraction between the germ-cells, which isin some cases so marked (for example in the polyp Renilla) thatwhen spermatozoa and ova are mixed in a small vessel, each ovumbecomes in a few moments surrounded by a dense fringe of sperma-tozoa attached to its periphery by their heads and by their move-ments actually causing the ovum to move about. The nature of theattraction is not positively known, but Pfeffers researches on thespermatozoids of plants leave little doubt that it is of a chemicalnature, since he found the spermatozoids of ferns and of Selaginellato be as actively attracted by solutions of malic acid or malates (con-tained in capillary tubes) as by the substance extruded from the.
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Keywords: ., bookcentury1900, bookdecade1900, booksubjectcells, bookyear1902
