the bones softened and the medullary substance hyperæmic, and claimed to produce rachitis in the former and osteomalacia in the latter. Both of these assertions were denied by Tripier and Toussaint, who insist upon Heitzmann's having selected animals which have a peculiar disposition to suffer from rachitis. Again, Milne Edwards and Boussaingault found the bones softened when they withdrew both phosphoric acid and lime from the food, without restoring the bone's consistency by administering powdered bone. But, lately, Ad. Baginsky states that he produced rachitis by withholding lime, and increased the effect by introducing lactic acid. By so doing, however, he changed only the relation of the mineral to the organic substances, without interfering with the normal proportions to each other of the constituents of the ashes. Beneke, finding oxalic acid in the urine in many cases of rachitis, attributes to it the want of calcification in rachitis, and Senator suggests that what impedes the deposition of bone might be formic, acetic, and lactic acids, which are also found in the young osseous tissue.[6] [Footnote 6: L. Fürth, _Path u. Ther. d. Rachitis_, Wiener Klinik, 1882.] Of these statements many are uniform, others contradictory. Thus far, they are not convincing except in one way--viz. that both withholding and introducing certain ingredients, mainly lime, influence the growth of the bone considerably. This may prove nothing else but that lime is of paramount importance in the building up of bone, and that bone in the period of rapid development is amenable to a great many influences.