ABSTRACT
In 1917 Miss Woodward and Miss Hague (5) published an account of experiments in which a solution of iodine in sea-water was found to be effective in producing artificial parthenogenesis in the eggs of Arbacia. The results were remarkable in that the percentages of the eggs which developed were not noticeably increased by treatment with hypertonic sea-water after activation by the parthenogenetic agent. In this respect iodine differs from all the better known means of producing artificial parthenogenesis in the echinoderm egg, and resembles only fertilisation by the spermatozoon, and the activation of the frog’s egg by pricking its surface.
It is better shown in the experiment recorded on the lower part of Fig. 3, in which the suspensions in sea-water and egg-water were respiring equally after 3 hours.
With two exceptions, in which the presence of thyroxine appeared to have no effect, least one of these the urchin from which the spermatozoa were derived was not completely ripe
