1448. The movement of the sap consists simply in an ascent and impulsion of its particles upon all sides, but without any circulation. A circulation would only be possible if the plant were an organism disengaged from the elements; but as the earth and air belong to its organization; it thus necessarily oscillates between both, and its movements also can only be oscillations of a similar intervening character.
1449. There are consequently no arteries and veins, and still less a heart in plants, as some have striven to make out.
1450. The vessels of plants are most properly to be compared with the lymphatic vessels of animals, the fluid or sap of which also tends from all parts towards one summit, namely, the lungs, while still at times retrogressive movements also seem to occur.
1451. The vegetable sap does not move in a straight line upwards, but in all directions, to the right and left, in a zigzag manner, and so on. This is proved by two incisions being made in a branch opposite to each other. The motion of the sap in the plant is more an impulsion of the sap toward all sides, with a predominance in the direction upwards, than a rapid current as in the blood. If we reflect that the motion of the sap when seen under the microscope and then magnified several hundred times, still only resembles a gentle rippling of small drops, it thus becomes clear that the true current or flow occurs only in a very tardy manner. Wherever therefore in the plant the process of differencialization may be brought into play, there the sap is impelled.
1452. Through the polarization of the sap the cells also become polar towards each other, and then even the cell-walls, whereby the cellular sap with its mucous granules is kept in constant motion. The theory of the motion of sap has not consequently been based upon the theory of capillary tubules; nor is heat alone the cause of its ascent; nor the empty space, which originates superiorly by evaporation; nor electricity in an inorganic sense.
II. FUNCTIONS OF THE FLORAL-ORGANS.
1453. These functions correspond to those of the light, heat, and gravity in the corolla, pistil and seed. The corolla irradiates, the pistil gives out heat, the seed sinks like the earth towards the centre.
1. Function of the Corolla.
FERTILIZATION.
1454. As in the vegetable trunk the principle function has been the antagonism between the aerial and the terrestriaqueous plant, so must the same function be repeated in the corresponding organs of the blossom. It oscillates in the principal antagonism between the corolla and pistil, which is the antagonism of leaf and stem, that of electrism and chemism, of light and body, of spirit and matter.