786 SPECIAL PHYSIOLOGY. 



the rate of their passage from the stomach to the kidneys saline sub- 

 stances, for example, passing more rapidly than coloring matters. 

 The relative diifusibility of the substances may also modify the result. 

 Pigments pass but slowly, indigo and madder requiring fifteen minutes, 

 rhubarb and biliary pigments twenty minutes, logwood and other col- 

 oring matters, twenty five minutes. 



It has been seen that many substances which are formed in, or be- 

 long to, the body, are liable to enter the urine, viz. : pus, fatty mat- 

 ters, certain biliary products, sugar, inosite, leucin, allantoin, tyrosin, 

 sarcin, hsematin, fibrin, and albumen. If bile be no longer separated 

 from the blood in the liver, or if its discharge by the alimentary canal 

 be prevented, it may appear in the urine, as it will in any other secre- 

 tion or excretion ; this happens in certain organic diseases of the liver. 

 But, in the more common form of jaundice, the bile pigments only pass 

 into the urine, giving it a dark color. The sugar which appears in 

 the urine, in diabetes (p. 748), is not produced in the kidneys, nor 

 does its presence in the urine necessarily imply disease of those or- 

 gans ; a larger quantity than usual being present in the blood, it 

 escapes through the excreting structure of the kidneys. Its increased 

 amount in the blood depends on an abnormal action of the liver, or on 

 the imperfect oxidation of the sugar in the blood, through some defect 

 in the respiratory process. The transitory appearance of sugar in the 

 urine is not of much consequence ; but its persistence, in diabetes, is 

 serious. A minute trace constantly occurs in healthy urine, though 

 it escapes ordinary tests. (Briicke.) The presence of albumen in the 

 urine is important, especially if persistent. If temporary, it indicates 

 pressure, or a great attenuation of the blood, or else an increased 

 pressure on the blood in the renal arteries. Thus, drinking enormous 

 quantities of water has been known to produce temporary albuminuria 

 or albuminous urine ; on the other hand, albumen is sometimes met 

 with in this fluid after indulgence in very full meals, or in cases where 

 the heart's action is, materially increased; or, again, where the aorta 

 is compressed below the renal arteries, or from renal congestion or in- 

 flammation, produced either by cold applied to the skin, or by the 

 undue use of diuretics or irritants, such as the, Spanish fly ; possibly, 

 also, by division of the renal sympathetic nerves. (Krimer.) The oc- 

 currence of albuminoid matter, after full meals, may be accounted for 

 by the probable introduction into the blood under those circumstances, 

 of more or less albuminose, which has a higher osmotic tendency than 

 albumen itself; when injected into the veins, it, indeed, appears in the 

 urine. Again, ligature of the aorta, below the renal arteries, in ani- 

 mals, or the forcible injection of blood through those vessels, causes 

 an artificial albuminuria. Persistent albuminous urine indicates some 

 degeneration of the excreting tissues of the kidneys, usually consisting 

 of the so-called granular degeneration, or " Bright's disease," the re- 

 sult of interstitial deposits of an albuminoid, fatty, or amyloid nature. 

 In such cases the lateral pressure of the blood in the capillary vessels 

 of the kidneys is increased, either by the obstruction of the circulation 

 through them, or as a result of the non-performance of the ordinary 

 excreting process. Besides the albumen of the blood, even the plastic 



