PATHOLOGICAL URINE 131 



a minute, and it becomes so intensely dark red as to be opaque. Now do 

 the same experiment with normal urine. An orange-red colour appears 

 even in the cold, and is deepened by boiling, but it never becomes opaque, 

 and so the urine for clinical purposes may be considered free from sugar. 

 This reduction of picric acid by normal urine is due to creatinine (see p. 123). 



The full significance and causes of pathological urine cannot be 

 appreciated until a theoretical and practical acquaintance with disease 

 is obtained, and we shall briefly consider only those abnormal con- 

 stituents which are most frequently met with. 



PROTEIDS IN THE URINE 



There is no proteid matter in normal urine, and the most common 

 cause of the appearance of albumin in the urine is disease of the 

 kidney (Bright's disease). The best methods of testing for and esti- 

 mating the albumin are given in the practical heading to this lesson. 

 The term ' albumin ' is the one used by cHnical observers. Properly 

 speaking, it is a mixture of serum albumin and serum globulin. 



A condition called ' peptonuria,' or peptone in the urine, is ob- 

 served in certain pathological states, especially in diseases where 

 there is a formation of pus, and particularly if the pus is decomposing 

 owing to the action of a bacterial growth called staphylococcus ; one 

 of* the products of disintegration of pus cells appears to be peptone ; 

 and this leaves the body by the urine. The term ' peptone,' however, 

 is in the strict sense incorrect ; the proteid present is deutero- 

 proteose. In the disease called ' osteomalacia ' a proteose is usually 

 found in the urine, which more nearly resembles hetero-proteose in 

 its characters. 



SUGAR IN THE URINE 



Normal urine contains no sugar, or so Httle that for clinical pur- 

 poses it may be considered absent. It occurs in the disease called 

 diabetes mellitus, which can be artificially produced by puncture of 

 the medulla oblongata, by extirpation of the pancreas, and by the 

 administration of the drug called phloridzin. The disease as it occurs 

 in man may be due to disordered metabolism of the liver, to disease 

 of the pancreas, or to other not fully understood causes. Transitory 

 glucosuria is found in many diseases. 



The methods usually adopted for detecting and estimating the 

 sugar are given at the head of this lesson. The sugar present is 

 dextrose. Lactose may occur in the urine of nursing mothers. 

 Diabetic urine also contains hydroxybutyric acid, and may contain 

 or yield on distillation acetone and £thyl-diacetic acid. 



k2 



