CH. XXXVII.] PATHOLOGICAL URINE 571 



fro a dozen times without shaking. Allow the corked tube to stand upright twenty- 

 four hours ; then read off on the scale the height of the coagulum. The figures indi- 

 cate grammes of dried albumin in a litre of urine. The percentage is obtained by 

 dividing by 10. Thus, if the coagulum stands at 3, the amount of albumin is 3 

 grammes per litre, or 0'3 gr. in 100 c.c. If the sediment falls between any two 

 figures, the distance |, i, or f from the upper or lower figure can be read off with 

 sufficient accuracy. Thus, the surface of the sediment being midway between 3 and 

 4 would be read as 3 '5. When the albumin is so abundant that the sediment is 

 above 4, a more accurate result is obtained by first diluting the urine with one or 

 two volumes of water, and then multiplying the resulting figure by 2 or 3, as the 

 case may be. If the amount of albumin is less than *05 per cent, it cannot be 

 accurately estimated by this method. 



A condition called " peptonuria," or peptone in the urine, is 

 observed in certain pathological states, especially in diseases where 

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

 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," how- 

 ever, is in the strict sense of the word incorrect ; the proteid present 

 is deutero-proteose. In the disease of bone called " osteomalacia " a 

 proteose is also usually found in the urine. This more nearly 

 resembles hetero-proteose in its properties. 



Sugar. Normal urine contains no sugar, or so little that for 

 clinical purposes it may be considered absent. It occurs in the 

 disease called diabetes mellitus, which can be artificially produced by 

 puncture of the medulla oblongata, or by extirpation of the pancreas. 

 The disease as it occurs in man may be due to disordered metabolism 

 of the liver, to disease of the pancreas, and to other not fully under- 

 stood causes (see p. 516). 



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 ethyl- 

 diacetic acid. The methods usually adopted for detecting and 

 estimating the sugar are as follows: 



(a) The urine has generally a high specific gravity. 



(/>) The presence of sugar is shown by the reduction (yellow precipitate of 

 cuprous oxide) that occurs on boiling with Fehling's solution. Fehling's solution is 

 an alkaline solution of copper sulphate to which Rochelle salt has been added. The 

 Rochelle salt (double tartrate of potash and soda) holds the cupric hydrate in 

 solution. Fehling's solution should always be freshly prepared, as, on standing, an 

 isomeride is formed from the tartaric acid, which reduces the cupric to cuprous 

 oxide. Fehling's solution should, therefore, always be tested by boiling before it is 

 used. If it remains clear on boiling, it is in good condition. 



(c) Picric Acid Test. Take a drachm (about 4 c.c.) of diabetic urine; add to it 

 an equal volume of saturated aqueous solution of picric acid, and half the volume 

 (/.., 2 c.c.) of the liquor potassae of the British Pharmacopoeia. Boil the mixture 

 for about 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. 564). 



