DILUTION MEDIUM AND SURVIVAL OF THE SPERMATOZOA OF ARBACIA PUNCTULATA. II. EFFECT OF THE MEDIUM ON RESPIRATION

¹ Department of Zoology, University of Missouri, Columbia, Missouri

1. Seminal fluid has the property of delaying the fall of respiratory activity of the sperm after the original burst of activity upon dilution.

2. Gray's "theory of exponential decay" is not adequate to explain sperm metabolic activity, whereas the "theory of autointoxication" fits the activity of sperm cells suspended in seminal fluid.

3. The seminal fluid delays appreciably the onset of an irreversible destruction of part of the metabolic system.

4. Fertilization studies have led to the formulation of a tentative mechanism based on the adsorption of a protein substance and its removal from the surface of the sperm cell.

5. The proposed mechanism also explains adequately the results of the respiration experiments. Therefore, it is concluded that a seminal fluid factor, by its action while on the surface of the sperm, influences both the fertilizing capacity and the respiratory rate of spermatozoa.

6. Egg water added to a sperm suspension after the original dilution, causes a sharp decrease in the respiratory rate.