Artificial parthenogenesis and fertilization / by Jacques Loeb... Originally tr. from the German by W. O. Redman King... supplemented and revised by the author.

  • Loeb, Jacques, 1859-1924.
Date:
[1913]
Catalogue details

Licence: In copyright

Credit: Artificial parthenogenesis and fertilization / by Jacques Loeb... Originally tr. from the German by W. O. Redman King... supplemented and revised by the author. Source: Wellcome Collection.

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    treating them for two miimtes with 50 c.c. of sea-water+2.9 c.c. N/lO butyric acid (which was thoroughly mixed). One portion of the eggs (A) was placed at once in Hypertonie sea-water (50 c.c. of sea-water+8 c.c. m NaCl), a second portion (B) thirty minutes later, and a third portion (C) after two hours. At intervals of five minutes a portion of the eggs was replaced in normal sea-water, the number of eggs undergoing Segmenta- tion ascertained, and, on the following day, the number of larvae that had been produced was counted. Table VI gives the result. The upper horizontal line shows how long (in minutes) the eggs remained in the Hypertonie solution and underneath is shown the percentage of the eggs in each part that grew into larvae. TABLE VI Percentage of the Eggs Which Developed into Larvae after ReMAINING in THE SOLUTION 5' 10' 15' 20' 25' 30' 35' 40' 45' 50' A 0 0 0 0 0 1 30 90 99 100 ß 0 0 1 2 40 70 90 98 C 0 1 4 10 30 70 90 100 The temperature of the Hypertonie solution was 15° C. What is the cause of this Variation in time required for the exposure to the Hypertonie solution? I suspect that it has something to do with changes which occur in the egg after the membrane formation. One of these changes is the formation of a fine gelatinous layer around the cytoplasm, which does not begin until at least ten or fifteen minutes after the membrane formation. It may be that the Hypertonie solution only or mainly takes effect after a definite change has taken place in the egg. y In all the experiments hereafter mentioned, the eggs were transferred some ten minutes after membrane formation; hence the length of exposure is somewhat as in series A.