It is not impossible that phosphorus, in substance, not in any of its compounds, may prove of great utility in the treatment of rachitis. Minimal doses of phosphorus render the newly-formed tissue at the points of apposition of the bones more compact in a very brief time. The new formation of blood-vessels in the osteogenous tissue gets retarded by it. Larger doses of phosphorus, however, increase vascularization, and osseous tissue is either less rapidly formed or even softened. When the doses are still larger, vascularization and softening may rise to such a point as to separate the epiphysis from the diaphysis. Thus the administration of the drug results in an irritation which, according to the doses employed, may give rise either to normal condensation or to inflammatory disintegration. This experience, arrived at by Wegner in a great many experiments made on animals, Kassowitz has confirmed. For its therapeutic effect he tried phosphorus in 560 cases of rachitis. Employing doses of one-half milligramme (one one-hundred-and-twentieth of a grain) several times daily (less will suffice), he soon found the skull to become harder, the fontanel smaller, the softening of the bones of the thorax and extremities to disappear, and all the other symptoms of rachitis to improve. This result was obtained though no particular change in the feeding of the patients was resorted to. To what extent this experience will be verified by others we shall soon learn. My own is already sufficiently extensive to base upon it a strong recommendation of the plan of treatment I have detailed. My therapeutical results in other diseases of the bones also encourage me to believe that phosphorus will accomplish much in the treatment of rachitis. Ever since Wegner's publications--viz. these thirteen or fourteen years--I have utilized phosphorus in cases of chronic and subacute inflammations of the bones, mainly of the vertebral column and the ankle-joint and tarsus. After having taught the method for many years in my clinic and otherwise, I made a brief communication on the subject to the Medical Society of the State of New York.[22] Since that time, again, I have followed the same plan in many cases of the same description, and feel sure that the prognosis in this serious class of bone diseases has become more favorable and recovery speedier. Infants of a year or more were given a dose of one-eightieth or one one-hundredth of a grain of phosphorus daily. One grain, dissolved in an ounce of oil or cod-liver oil, is a convenient mixture, four or six drops of which may be administered daily in two or three doses. [Footnote 22: _Trans._, 1880.]