ACTIVITY-PREVENTING AND EGG-SEA-WATER NEUTRALIZING SUBSTANCES FROM SPERMATOZOA OF ECHINOMETRA SUBANGULARIS

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Abstract
1. Dry sperm of Echinometra subangularis is intensely active immediately after its removal from the testes tubules, but this motion lasts for but from 50 to 120 seconds, when all activity ceases. When, however, a drop of sea-water is brought in contact with such a drop of dry sperm, the spermatozoa again become active, and this activity continues for from three to four hours. The addition of another drop of sea-water will cause the spermatozoa again to become active, and this activity continues with gradually decreasing intensity for about one and one-half hours. Such spermatozoa can again be reactivated, but the length of time during which they remain active progressively decreases, until finally, no further activation is obtained. 2. This inactivation of sperm suspensions with time is caused, probably, by the accumulation of a substance with time which has, as its characteristic identificatory property, the prevention of spermatozoa from activity. It occurs in the supernatant fluid obtained from centrifuging dry sperm, and in the supernatant fluid obtained by washing dry sperm through ordinary sea-water several times with the centrifuge, but the suspensory fluid of diluted sperm suspensions through which the spermatozoa have not been washed does not contain the substance in detectable amounts. 3. Supernatant fluid which contains this substance also, in all cases, has the property of neutralizing the agglutinating power of egg-sea-water, and there seems to be a parallelism between ability to prevent activity of dry sperm and ability to neutralize egg-sea-water. 4. These observations indicate that the activity-preventing and the egg-sea-water neutralizing properties of supernatant fluid are due, either to the same substance, or to two substances which, however, occur together under all the treatments where the effects have been observed.

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