[252] These have been translated for the "Bibliothèque Britannique, Section des Sciences et Arts," vol. lii.
[253] Treviranus, "Die Erscheinungen und Gesetze des Organischen Lebens" (Phenomena and Laws of Organic Life), vol. i. p. 173.
[254] Brandis, "On Life and Polarity," 1836, p. 88, says: "The roots of rock-plants seek nourishing mould in the most delicate crevices of rocks. These roots cling to a nourishing bone in dense clusters. I saw a root whose growth was intercepted by the sole of an old shoe: it divided itself into as many fibres as the shoe-sole had holes--those by which it had been stitched together--but as soon as these fibres had overcome the obstruction and grown through the holes, they united again to a common stem." And p. 87: "If Sprengel's observations are confirmed, even mediate relations are perceived (by plants) in order to obtain this end (fructification): that is to say, the anthers of the _nigella_ bend down in order to put the pollen on the bees' backs, and the pistils bend in like manner to receive it from the bees." [Add. to 3rd ed.]
In Froriep's "Memoranda" for 1833 (No. 832) there is a short article upon the locomotivity of plants: in poor soil, where good mould lies near at hand, many plants will send out a shoot into the good mould; after a time the original plant then withers, but the offshoot prospers and itself becomes the plant. By means of this process, a plant has been known to climb down from a wall.
In the same periodical (1835, No. 981) is to be found a communication from Professor Daubeny, of Oxford (taken from the "Edinburgh New Philosophical Journal," April-July, 1835), in which he shows with certainty, by means of new and very careful experiments, that roots of plants have, at any rate to a certain degree, the power to make choice from those substances in the soil which present themselves to their surface.[255]