3 14 PHYSIOLOGICAL CHEMISTRY. 



ALBUMIN. 



Albuminuria is a condition in which serum albumin or serum 

 globulin appears in the urine. There are two distinct forms of 

 albuminuria, i. e., renal albuminuria and accidental albuminuria. 

 Sometimes the terms " true " albuminuria and " false " albuminuria 

 are substituted for those just given. In the renal type the albumin 

 is excreted by the kidneys. This is the more serious form of the 

 malady and at the same time is more frequently encountered than 

 the accidental type. Among the causes of renal albuminuria are 

 altered blood pressure in the kidneys, altered kidney structure, or 

 changes in the composition of the blood entering the kidneys, thus 

 allowing the albumin to diffuse more readily. In the accidental 

 form of. albuminuria the albumin is not excreted by the kidneys as 

 is the case in the renal form of the disorder, but arises from the 

 blood, lymph or some albumin-containing exudate coming into con- 

 tact with the urine at some point below the kidneys. 



EXPERIMENTS. 



i. Heller's Ring Test Place 5 c.c. of concentrated HNO 3 in a 

 test-tube, incline the tube, and, by means of a pipette allow the 

 urine to flow slowly down the side. The liquids should stratify 

 with the formation of a ivhite zone of precipitated albumin at the 

 point of juncture. If the albumin is present in very small amount 

 the white zone may not form until the tube has been allowed to 

 stand for several minutes. If the urine is quite concentrated a 

 white zone, due to uric acid or urates, will form upon treatment with, 

 nitric acid as indicated. This ring may be easily differentiated 

 from the albumin ring by repeating the test after diluting the urine 

 with 3 or 4 volumes of water, whereupon, the ring, if due to uric 

 acid or urates, will not appear. It is ordinarily possible to differ- 

 tiate between the albumin ring and the uric acid ring without 

 diluting the urine, since the ring, when due to uric acid, has ordi- 

 narily a less sharply defined upper border, is generally broader than 

 the albumin ring and frequently is situated in the urine above the* 

 point of contact with the nitric acid. Concentrated urines also oc- 

 casionally exhibit the formation, at the point of contact, of a crys- 

 talline ring with very sharply defined borders. This is urea nitrate 

 and is easily distinguished from the "fluffy" ring of albumin. If 

 there is any difficulty in differentiation a simple dilution of the urine 

 with water, as above described, will remove the difficulty. Various 



