The relation of spermatozoa to certain electrolytes.—II
The fact that living spermatozoa move towards the positive pole of an electric field has been known for some years. In a note published in 1915, the writer (8) pointed out that this movement is dependent upon a certain concentration of hydroxyl ions, without which the spermatozoa neither exhibit their normal activity nor do they move in an electric field. In the same paper the behaviour of spermatozoa to such trivalent ions as cerium was briefly described. In the present communication these results are enlarged, and the problem briefly discussed from its theoretical aspect. A considerable mass of evidence now exists to show that the surface charge of a particle or membrane is profoundly affected by the nature of the solution with which it is in contact. Albumen particles, when suspended in an acid medium, are positively charged; when in an alkaline medium they are negatively charged. Perrin (11) has shown that, if a diaphragm separates two phases between which a potential gradient exists, then the gradient can increase or decrease by treating the diaphragm with various agents. In acid solutions a negative diaphragm becomes less negative, and finally positive; in an alkaline solution the negative charge is increased.