In view of contributing to the discussion about the rickets of newborn, whether an antenatal factor can play an etiological role or not, a following experiment was carried out. White rats were used as experimental animals, and a diet provoking rickets after Steenbock No. 2965 was administered, the component of which being partially changed. Then the rats were made to couple with healthy males fed with normal diet (rice, dried fish, green) and pregnancy was thus repeated in order to obtain youngs in different series. Of the newborns were examined, the body weight, the number of the same litter, histological and roentgenological findings of the bones, chemical analysis of calcium and elementary phosphorous in the bones etc. As the contrast healthy normal youngs were examined at the same time, On the other hand, the youngs of the experiment as well as of the contrast were fed with the rachitic diet from the beginning of the third week after birth and in a long duration of ten or fifteen weeks roentgenological and histological examinations were carried out at different times for the purpose of ascertaining the eruption of rachitic symptomes. The results of the experiment are summarized as follows: 1) During the experiment, the animals lost sometimes the gloss of the fur and became rough-furred. When pregnancy and delivery was repeated, the fur was pulled out to a large extent. The sexual cycle remained regular for a comparatively long time, but it ceased finally, if pregnancy was repeated. 2) By administering the rachitic diet, it was ascertained that the abortion or premature interruption of pregnancy and resorption of intrauterine fetuses took place in a marked degree. The longer the feeding with the rachitic diet, the more marked was this tendency. 3) By feeding with the rachitic diet for a certain time, the animals acquired a condition of low amount of blood phosphorous and symptoms of osteomalacia revealed by roentgen and histoiogical examinations. 4) In the newly born youngs there was no especial change in the body weight, the number of the litter and in the histological findings of the bones, but the amount of calcium in the bones was lowered to a moderate extent. 5) The bodily development of the youngs was general1y bad; those in the experiment being worse than in the contrast, and as time elapsed, the difference became more and more marked. 6) All the Wborns finally acquired the symptoms of rickets; those in the experiment were more rapid in its eruption and more marked in its begree than in the contrast.
From the above-results it can be stated that the newborns from the mother fed with the rachitic diet during pregnancy acquired a disposition liable to the rickets or in other words, they were born in a condition of "praerachitis". An antenatal factor was thus revealed to play an important role in the causation of the rickets.