The Ceylon sportsman, in shooting elephants, aims at a spot just above the proboscis. If he fires a little too low, the ball passes into the tusk-socket, causing great pain to the animal, but not endangering its life; and it is immediately surrounded by osteo-dentine. It has often been a matter of wonder how such bodies should become completely imbedded in the substance of the tusk, sometimes without any visible aperture; or how leaden bullets become lodged in the solid centre of a very large tusk without having been flattened, as they are found by the ivory-turner. The explanation is as follows: A musket-ball aimed at the head of an elephant may penetrate the thin bony socket and the thinner ivory parietes of the wide conical pulp-cavity occupying the inserted base of the tusk; if the projectile force be there spent, the ball will gravitate to the opposite and lower side of the pulp-cavity. The pulp becomes inflamed, irregular calcification ensues, and osteo-dentine is formed around the ball. The pulp then resumes its healthy state and functions, and coats the osteo-dentine enclosing the ball, together with the root of the conical cavity into which the mass projects, with layers of normal ivory. The hole formed by the ball is soon replaced, and filled up by osteo-dentine, and coated with cement. Meanwhile, by the continued progress of growth, the enclosed ball is pushed forward to the middle of the solid tusk; or if the elephant be young, the ball may be carried forward by growth and wear of the tusk until its base has become the apex, and become finally exposed and discharged by the continual abrasion to which the apex of the tusk is subjected.--_Professor Owen._ NATURE OF THE SUN. To the article at pp. 59-60 should be added the result obtained by Dr. Woods of Parsonstown, and communicated to the _Philosophical Magazine_ for July 1854. Dr. Woods, from photographic experiment, has no doubt that the light from the centre of flame acts more energetically than that from the edge on a surface capable of receiving its impression; and that light from a luminous solid body acts equally powerfully from its centre or its edges: wherefore Dr. Woods concludes that, as the sun affects a sensitive plate similarly with flame, it is probable its light-producing portion is of a similar nature.