The Day After Death (New Edition). Our Future Life According to Science. Figuier Louis

of the sun. It is by means of the respiration of the plants, which restores oxygen to the atmospheric air, that nature makes up for the withdrawal of oxygen by the respiration of animals, by the continual absorption of that gas by numerous mineral substances, and by the frequent combustions, natural and artificial, which occur in the world. The result of these combustions would be the disappearance of the greater portion of the oxygen contained in the air, if there did not exist a permanent machinery for the restitution of that oxygen. This permanent machinery is the respiration of plants, produced by solar light. So absolute is the dependence of plants for their respiration on the action of the sun's light, that if it be intercepted by clouds, the escape of oxygen from them suffers a marked diminution. If the light of the sun be suddenly stopped, which occurs during a total solar eclipse, the escape of oxygen ceases, and the plants transpire carbonic acid only, as they always do during the night.

      It is for this reason that a plant kept in complete darkness loses its colour, and becomes white. It does not respire, it emits carbonic acid gas without retaining carbon, it becomes etiolated, according to the scientific phrase, which means that the plant no longer lives at the cost of the external air, or of gas furnished by the soil, but consumes its own substance. The whitened salads which we prefer are not green only because they are grown in darkness, and the mushrooms brought to table are white only because they are reared in cellars.