It is in the period of rapid development that rachitis is observed. Thus it occurs in every stage of intra-uterine and infant life. It is met with in the foetus in very early intra-uterine life; it is found as a congenital affection, continuing to develop after birth when it has originated in the latter half of foetal existence; there is, thirdly, the rachitis of early infancy; and, lastly, that of advanced infancy and childhood. Of 624 cases of rachitis enumerated by A. Baginsky, there were 256 less than a year old, 313 in the second, and 63 in the third year. After this time rachitis is rare, as far as the active symptoms of the disease are concerned. But still, a retarded form of rachitis (r. tardiva) has been described by some authors. It is said to occur about puberty, and to exhibit local changes in the bones of genuine rachitical character, but to be wanting in all the other symptoms required for the diagnosis of general rachitis. Such cases have been described {142} by C. Lucas.[7] He found it complicated, now and then, with albuminuria. The occurrence of the latter at that time of life had been referred to by Moxon.[8] The principal symptoms described by Lucas are scoliosis, talipes valgus, and genu valgum. The epiphyses were slightly thickened; there were pain in the limbs, languor, and pallor. In some of the cases there were also rachitical deformities dating from infancy. He believes rachitis of adolescence to exhibit more symptoms belonging to relaxation of the ligaments than to softening of the bones. [Footnote 7: _Lancet_, June 9, 1883.] [Footnote 8: _Guy's Hosp. Rep._, 1878.] A case of rachitis of undoubtedly congenital nature has been reported by Chiari. There were but twelve teeth. There were no other alveoli, nor was there any intimation of the formation of alveoli in the shape of the jaw, which resembled very much the usual senile form of retrograde metamorphosis.