Artificial parthenogenesis and fertilisation : a review / by Thomas H. Bryce.

  • Thomas Hastie Bryce
Date:
[1902]
Catalogue details

Licence: In copyright

Credit: Artificial parthenogenesis and fertilisation : a review / by Thomas H. Bryce. Source: Wellcome Collection.

Provider: This material has been provided by The Royal College of Surgeons of England. The original may be consulted at The Royal College of Surgeons of England.

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    pressure in various other ways (Loeb). This may be done by adding various inorganic salts to the sea water, especially the salts of magnesium, potassium, sodium, and calcium, in definite proportions (Loeb, Morgan, and others), or by adding sugar or urea (Loeb). Other salts have also given results, e. g. chloride of manganese (Delage). The effect is produced when the eggs, after being left from half an hour to two hours in the solution, are transferred to pure sea water, and is due to the disturbance of the osmotic pressure leading to loss of water by the egg, followed by reliydration (Bataillon, Loeb, Griard, etc.), not to specific chemical stimulation. The nuclear activity may also be roused by other chemical bodies, as strychnine (Hertwigs, Morgan), chloroform, ether, alcohol, by lack of oxygen (Mathews), by very dilute hydro- chloric acid (Loeb, Delage). Further, purely physical agents may have the same effect— heat (Mathews, Bataillon, Delage, Viguier), cold (Morgan, Greeley), and, most important, agitation (Mathews). Mathews had previously proved for Asterias, and Morgan for Arbacia also, that shaking of unripe eggs caused them to form the polar bodies—the shaking presumably causing dissolution of the nuclear membrane. Ripe eggs of Asterias, but not of sea- urchin, act in the same way, but only after they have lain some time in water; after two hours larvae begin to appear on shaking; after four hours, hard shaking produces a large proportion of larvae, and the mere transference of the eggs by a pipette from one vessel to another is sufficient to form a few larvae. A few hours later the slight amount of shock experienced in the transference of the eggs, causes a large number to begin to develop, though they do not go beyond the late segmentation stages. At this time shaking causes all to develop, but none reach the blastula stage. Loeb and Fischer have extended this observation to the Annelids, Chaetopterus and Amphitrite. The mitotic phenomena produced artificially are apt to be irregular, and the division of the cell body is often unequal
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