A further factor is suggested by the action of certain diuretics. In the kidney the changes in the quantity of blood flowing through the organ and to some extent changes in blood pressure influence the flow of urine. The diuresis produced by such substances, however, as saponin, digitalin, potassium chlorate, etc., probably depends on an increase in permeability of the capsule of Bowman. As shown[91] recently, these substances produce haemolysis, and are also strong diuretics. Calcium chloride, which inhibits the flow of urine produced by them, inhibits also the haemolysis. Haemoglobinuria, which readily appears with small doses of saponin or digitalin, is inhibited by simultaneously injecting calcium chloride. There thus seems to be something in common between haemolysis and diuresis; and what suggests itself as most probable is that the permeability of the red blood corpuscle, as well as that of the kidney cell is increased, so that on the one hand haemoglobin escapes into the blood (is secreted into the blood), and the amount of urine on the other hand passing through the kidney cell is increased. Calcium, according to the same idea, would decrease the permeability in both cases. In secretion we have therefore among other things two factors which probably play a rôle, namely, a property of the gland cell resembling that of muscular contractility and controlled in many cases by the same conditions, and a change in permeability of the cells which are secreting. In the kidney there is a third factor dependent on the flow of blood through the organ. A continuous supply of blood is of course necessary in all glands for a continued secretion. FOOTNOTES: [76] Recherch. expériment. sur les mouvements des liquides dans les tubes de petits diamètres, Paris, 1828. Quoted from Hay. [77] Über die Saftbewegung, 1848. [78] L’Union médicale, 1871, 50, 51. Gaz méd. de Paris, 1879. [79] Substances toxiques et médicamenteuses, 1857. [80] Action of Medicines, 1867. [81] Archiv. général d. médicine, VI Série f. XVI, 1870. Centralbl. f. d. medicin. Wiss., 1868, p. 209. [82] Arch. f. exp. Path. u. Pharm., Bd. VIII, 1878, S. 355. [83] Reichert’s u. DuBois-Reymond’s Archiv, 1870, S. 37. [84] Pflüger’s Archiv, 1872, S. 266. [85] _Loc. cit._ [86] Arzneimittellehre, Leipzig, 1883. [87] Amer. Journ. Physiol., 1898, Vol. I, p. 411. [88] LOEB: Decennial Publications, University of Chicago, Vol. X, 1902, p. 10. [89] MACCALLUM, J. B.: University of California Publications, Physiology, Vol. II, 1905, p. 65. [90] MACCALLUM, J. B.: University of California Publications, Physiology, Vol. I, 1904, p. 115. [91] MACCALLUM, J. B.: University of California Publications, Physiology, Vol. II, 1905, p. 93. CHAPTER X. Possible Therapeutic Value of These Experiments.