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PHYSIOLOGICAL BOTANY.

the stem, and then traverse it in its entire length. Nearthe periphery the vascular bundles are so crowded that itis difficult to separate them and ascertain their course.

Gaudichaud continues : “ We shall naturally apply thisprinciple to the growth of the stem, leaves, fruit, &c., andalso extend it to the flowers and other deciduous parts ofplants. We would also apply it to the stem of Vellosia,which, as it derives scarcely anything from the leaveswhich exist at the ends of the branches, always remainsvery thin, for the simple reason that the vessels of the rootsof the leaves which should produce the increased thicknessof the stem, become applied immediately after their for-mation to the external part of the bark {a V exterieur duperixyle), and thus descend as roots (a Vetat de ratines),along the twigs, the branches, and leaves, to the ground.The primordial leaf (that first formed after the embryo),undoubtedly obtains life and nutriment, but nothing fur-ther, from the embryo; the primordial leaf also impartsvitality and its principal nutriment to the second leaf, andthe same occurs with the second leaf in regard to thethird, &c.”

Gaudichaud always writes in this aphoristic style,which becomes more remarkable from his separating thesentences from each other, and commencing a new line.

Again, he says (1. c. p. 610): “ In fact, since it is foundby observation, that the embryo, this small isolated being,consists originally of cellular tissue only, and that thiscellular tissue produces the vessels by its physiologicalaction; that the vessels commence in the internodes ofthe stem ( merithale tiyillaire), then appear in the petiolaryand the laminary merithals of the leaf; that they are per-fectly formed, or at least may be traced in these regions(dans lesparties merithalliennes), before they appear in thepapilla of the rootlet ( mammelon radiculaire ), we are ledby analogy to consider that the same must also be the casewith the organization of other individuals, of whateverkind they may be, which are produced by plants. Thisfact I repeat is an important one, and worthy of conside-