. The cell; outlines of general anatomy and physiology. by the embryonic substance is partitionedout, so that anticlinal and periclinal walls intersect at right being granted, the network of cells in Fig. Ill may be con-structed according to a well-known geometrical law. Let x x re-present the axis, and y y the direction of the parameter, then allthe periclines, denoted by P p, form a group of confocal , all the anticlines, A a, form another group of confocalparabolas, whose focus and axis coincide with those of the pre-ceding group, but which run in the opposite
. The cell; outlines of general anatomy and physiology. by the embryonic substance is partitionedout, so that anticlinal and periclinal walls intersect at right being granted, the network of cells in Fig. Ill may be con-structed according to a well-known geometrical law. Let x x re-present the axis, and y y the direction of the parameter, then allthe periclines, denoted by P p, form a group of confocal , all the anticlines, A a, form another group of confocalparabolas, whose focus and axis coincide with those of the pre-ceding group, but which run in the opposite direction. Two suchsystems cut one another everywhere at right angles. Let us now observe whether a median longitudinal section madethrough a dome-shaped, and approximately parabolic growing-point, does not present an arrangement of cells which correspondsin all essentials with our geometric diagram. We see at once, if weexamine such a section, made from the growing-point of a Larchfor example (Fig. 112), that the internal structure is identical, if. Fig. 112.—Longitudinal section through the growing-point of a winter bud of Abiesrectinata (x about 200) (after Sachs, Fig. 235): 5 apex of growing point; bb youngestleaves ; r cortex ; m pith. we disregard the two protuberances, b b, which interfere somewhatwith the symmetry of the figure. These are young leaf-rudiments,budding off from the growing-point. We recognise at once thetwo systems of anticlines and periclines, which it can scarcely bedoubted cut each other at right angles, as in the diagram; that isto say, the anticlines are the right-angled trajectories of the peri-clines. As in the diagram, further, only a few periclines underthe apex 8 run round the common focus of all the parabolas ; theothers, which come from below, only reach the neighbourhood of THE VITAL PHENOMENA OF THE CELL 223 the focus ; that is to say, the corresponding cell divisions onlyoccur after the periclines below the centre of curvature havebecome
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Keywords: ., bookcentury1800, bookdecade1890, bookidcelloutlines, bookyear1895
