Mr. Layard does not think that the extent of Nineveh has been exaggerated. The space within the ruined ramparts does not seem to have been occupied with houses. These ramparts merely surrounded the magnificent palaces and their beautiful grounds. The citizens resided beyond them, having the space within for a refuge in case of invasion. This is the plan of some modern cities in the East. From a careful survey of the whole ground, Mr. Layard believes that Nineveh was a "city of three days' journey round"--say, sixty miles in circumference. VEGETABLE PHYSIOLOGY. BY HARLAND COULTAS. PROCESS OF FERTILIZATION.--The young seeds or ovules are contained in the interior of the pistil before the flower opens, and continue to grow until that time, but no longer, unless they are acted upon by the pollen of the anthers. The necessity of this process shows why it is that stamens and pistils are so constantly found in flowers, and why the former surround the latter so nicely as they in general do; and, even in circumstances which seem somewhat adverse to fertilization, still some admirable contrivance is always found to bring about the same end. In some flowers, we meet with beautiful contrivances for securing the fecundation of their pistils. Thus, such as are erect have usually the stamens longer than the pistils, whilst in pendulous flowers it will be found that the pistils are the longest and the stamens the shortest. By this admirable relative adjustment, the pollen, in falling, comes into contact with the pistil. The Fuchsia, or ladies' ear-drop (Fig. 1), shows the character of this arrangement in a pendulous flower: _p_ is the pistil, and _s_ the stamens, which, it will be perceived, are much shorter, and situated above the pistil, in order that its viscid stigma or summit may receive the pollen as it falls out of the anther cells. [Illustration: Fig. 1.] There are a few well-known instances in which fertilization is effected by certain special movements of the stamens. The stamens of the barberry spring to the pistil, if the lower part of their filaments is touched; and in Parnassia palustris, the grass of Parnassus, a rare and beautiful snow-white swamp flower, the stamens move towards the pistil in succession to discharge their polliniferous contents.