On the Impregnation of the Ovum in the Amphibia; (Second Series, Revised.) and on the Direct Agency of the Spermatozoon. (from the Philosoph. Transactions. P. II for 1853.)

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General Books, May 15, 2012 - 32 pages
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This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1853 Excerpt: ...Thus too, I have noticed that, when from accident, but more especially when from reduction of the temperature in the surrounding medium, the season of spawning has been greatly retarded, the impregnating power of the male is much diminished, and perhaps is almost exhausted, through constant shedding of the spermatic fluid, which, I have found, often takes place when the oviposition of the female is delayed, and the individuals are disturbed or interfered with. The female is then forsaken by her partner, and when this occurs it rarely happens that the connubial intercourse of these two individuals is recommenced. When this separation has taken place, there is usually but a small quantity of fluid remaining in the male organs, and even in that, the number of spermatozoa is considerably diminished, and their power of motion is exceedingly feeble; while the quantity of molecules and cells is increased. When several days, or a week or two have elapsed, there are not only fewer spermatozoa, but those which remain are much more feeble in action. This is exactly what occurs also in the Toad. On the sixth of June I found that the testes and efferential ducts in a male Toad, which had been kept from pairing during the whole season, were still filled with spermatozoa, together with a very small quantity of liquor seminis with active molecules moving in it; but that, though the spermatozoa were in full abundance, nearly the whole of them were entirely motionless, while the motions of the few which still gave evidences' of vitality, were exceedingly feeble, whether the spermatozoa were examined simply in the fluid portion of the semen, or whether they were mixed with water, in which, as is well known, the motions are always at first greatly increased. Wagner and Leuckar...

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