{139} In regard to the elimination of phosphoric acid, the analyses of different periods do not agree any better. The conclusions of previous researches, pointing to a quadruple elimination of phosphoric acid in the urine of rachitis, are refuted by Seemann, who found no increase, and by Baginsky, according to whose researches the phosphoric acid of the healthy urine compares with that of rachitical urine as 40:12-37. As far as the elimination of nitrogen is concerned, there appears to be but little difference between normal and rachitical urine. Chlorine was found to be diminished in rachitis by Baginsky. Lehmann and Von Gorup found lactic acid several times. Several times albumen was met with; in a case of Ritchie's, blood; in one of Von Gorup's, fat.[4] [Footnote 4: E. Salkowski und W. Leube, _Die Lehre vom Harn_, 1882, p. 536.] The etiology of rachitis must be studied from two points of view. It has its predisposition and its direct and proximate causes. The former has been studied by F. W. Beneke[5] upon an anatomical basis. He finds that the arteries of rachitical patients are large all through the body. This is so particularly in the carotids; it seems probable that the changes taking place in the head are due to this anomaly in the size of the arteries. Three cases in which the width of the arteries of the neck was unusually large terminated fatally--one by hydrocephalus, one with a very large skull, and one suddenly. This width of the arteries is most marked, under ordinary circumstances, from the second to the fourth year; that is, the exact time in which (except the cases of early rachitis) the rachitical process is at its height. It is considered by Beneke to be the cause of the local increase of vascular irritation, particularly in the epiphyses with their retarded circulation; and also of the increase of nutritive development which is so often noticed during recovery from rachitis; and, finally, of the many pulmonary complications of an inflammatory nature. [Footnote 5: _Die Anatomischen Grundlagen der Constitutions Anomalien des Menschen_, 1878, p. 75, etc.] There is another interesting consideration in regard to the effect of wide arteries on the relations between the blood and tissues. A great many more blood-cells are required to fill the arteries when wide than when narrow. Now, the formation of blood-cells is hindered by any disease of the digestive and blood-preparing organs, so that the tissues are liable to show the relative increase in the percentage of water, which is uniformly confirmed for rachitis by the biochemists.