. The Electrical Conductivity of Echinoderm Eggs, and Its Bearing on the Problems of Fertilisation and Artificial Parthenogenesis. yl Ion upon the Conductivity of Unfertilised Eggs. Table XXII. Eggs. Strength of alkali. Decrease inresistance. After xminutes. Sphcerechinus Strongylocentrotus n 50 vant Hoffs solution + 0 • 25 N/10 NaOH + 0*25+ 0-5+ 0-75+ 0-75+ 0*25+ 0*25 )» jj >j ?j jj a per cent. 10 3 1 ?9 22 ?1 9 4 23 5 20 •9 11 8 6030 U 8 16 66 57 50 vant Hoffs solution + 025 N/10 NaOH = solution A; 50 vant Hoffs solution+ 0*5 N/10 NaOH = solution B ; 50
. The Electrical Conductivity of Echinoderm Eggs, and Its Bearing on the Problems of Fertilisation and Artificial Parthenogenesis. yl Ion upon the Conductivity of Unfertilised Eggs. Table XXII. Eggs. Strength of alkali. Decrease inresistance. After xminutes. Sphcerechinus Strongylocentrotus n 50 vant Hoffs solution + 0 • 25 N/10 NaOH + 0*25+ 0-5+ 0-75+ 0-75+ 0*25+ 0*25 )» jj >j ?j jj a per cent. 10 3 1 ?9 22 ?1 9 4 23 5 20 •9 11 8 6030 U 8 16 66 57 50 vant Hoffs solution + 025 N/10 NaOH = solution A; 50 vant Hoffs solution+ 0*5 N/10 NaOH = solution B ; 50 vant Hoffs solution + 0*75 N/10 NaOH = solution C. AND ITS BEARING ON FERTILISATION AND ARTIFICIAL PARTHENOGENESIS. 513 The results given in the above Table are what would be expected by a comparisonwith the effects of the citrate ions upon the conductivity of the eggs. Solution A# does not injure the eggs in any way. In solution B, however, theeggs tend to aggregate together ; while in solution C this condition is very C, and sometimes solution B, renders the eggs unhealthy after one or two 240. Fig. 5 10 15 zo zb 50 35 40 45 5o 55 Time in minutes -Illustrating the effects of hydroxyl ions upon the resistance of the unfertilised eggs of Splicer echinus granulans. hours. The aggregation of the eggs is usually less marked as soon as the eggs arevisibly affected by the alkali. Solution A produces a slow continuous fall inresistance. Exposure to solutions B and G induces a very sudden rise in the resist-ance, which is rapidly followed by a rapid and progressive fall in resistance. Thefinal resistance is always lower than that of the eggs at the beginning of theexperiment—which explains the figures given in Table XXII. VOL. COVII.—B. * See footnote to Table XXII, 3 Y 514 MR. J. GRAY ON THE ELECTRICAL CONDUCTIVITY OF ECHINODERM EGGS, Effect of Trivalext Positive Ions upon the Conductivity of Fertilised .Eggs. Table XXIII.—Splicerechinus Eggs. Min
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