STUDIES IN ARTIFICIAL PARTHENOGENESIS

Abstract

1. Dilute solutions of mercuric chloride in sea-water cause typical membrane elevation in the sea-urchin egg in spite of the fact that they presumably do not lower surface tension. 2. The action of the mercuric chloride is favored by aging the eggs. Eggs fresh from the ovary are not acted upon, and the percentage of membrane elevation on treatment with the sublimate solution increases in proportion to the time the eggs have stood in sea-water before being subjected to the reagent. 3. The favorable effect of aging is apparently due to the removal of carbon dioxide. The addition of carbon dioxide prevents membrane elevation by mercuric chloride. 4. If eggs are centrifuged one or two minutes after the treatment with mercuric chloride is begun, membrane elevation is generally prevented. 5. Solutions of mercuric chloride in contact with eggs lose their power of provoking membrane elevation. 6. The facts cited in 4 and 5 are regarded as evidence in favor of the view that mercuric chloride reacts with the jelly or cortex of the egg to form chlorine. Such a reaction is in accord with the usual behavior of mercuric chloride in the presence of organic materials. 7. Chlorine gas is effective in producing membrane elevation. 8. The action of mercuric chloride in causing membrane elevation is probably due to the formation of chlorine. Since chlorine has a very low surface tension, the fact that mercuric chloride causes membrane elevation can not be used as an argument against the surface tension theory.