PHYSIOLOGICAL ANALYSIS OF THE CORTICAL RESPONSE OF THE SEA URCHIN EGG TO STIMULATING REAGENTS. II. THE PROPAGATING OR NON-PROPAGATING NATURE OF THE CORTICAL CHANGES INDUCED BY VARIOUS REAGENTS

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Abstract
A special technique has been developed for partial exposure of a sea urchin egg surface to stimulating reagents under microscopical observation. The surfaces of Hemicentrotus eggs were partially exposed to stimulating reagents for an appropriate time and the unexposed surface was examined after washing with sea water. When wasp-venom, Na choleinate, monogen or Lipon was used, the cortical granules in the exposed cortex were completely broken down within a few minutes, while those in the unexposed cortex remained quite intact, showing no sign of the influence of the reagent. The effect of these reagents is believed to be of a non-propagating nature. When butyric acid, acetic acid, propionic acid, distilled water or an isotonic soln. of a non-electrolyte was used, the granular breakdown proceeded rapidly in the unexposed part of the cortex immediately after granule breakdown in the exposed part. Therefore, it is concluded that these reagents induce a cortical change of a propagating nature. It is suggested that the nature of the cortical change provoked by reagents of the latter group is essentially the same as that which follows the entrance of spermatozoa.