The following can now happen: Either these toxic products may be produced in such enormous quantities that even the increased functions of these glands will be insufficient to overcome them, or the glands may not be in a condition of complete integrity. In either of these cases the bulk of these poisons will be carried to the eliminating organs to be dealt with, viz.: the skin, the intestines, and the kidneys. As we shall see, the skin alone is not able to eliminate more than a certain portion of these products, even by the additional assistance of perspiration. In addition to the skin the intestines may also assist the work of the kidneys, by expelling principally the poisons from the digestive organs. But only a small portion of the poison circulating in the blood will be eliminated in this way, especially if there is a lazy action of these organs. Thus the great bulk of all these products is carried to the kidneys, which are, indeed, our most important organs for the elimination of toxic products from the blood. It is furthermore important to consider the kidneys because they are also glands with internal secretion. This is evident from the fact that uræmia is a condition which is dependent upon the absence of such a secretion.[220] It is not caused only by the retention of urine and the urea contained therein, for cases have been noted where there has been no urine for as long a time as seven days, and yet there was no uræmia, whereas uræmia rapidly develops at times in spite of an abundant flow of urine and elimination of urea. Thus, logically, uræmia must be ascribed to another factor, which can only be the absence of an internal secretion from the kidneys, which may otherwise perfectly perform their work. Another convincing proof of this statement is the fact that we are able to treat with great effect, as we have personally observed, diseased kidneys with extracts from the kidneys of pigs. We will demonstrate the action of this in a separate chapter. Footnote 220: Senator: Loc. cit., and others. That the kidneys are glands with internal secretion has been proved already by Brown-Séquard,[221] Meyer,[222] and other authors, among whom we will mention as two of the last authorities on this question, Professor Senator and Professor Hermann Strauss. Footnote 221: Brown-Séquard: Archives de physiologie norm. et path., p. 778, 1893. Footnote 222: Meyer: _Ibid._, p. 179, 1894.