CH. XII.] BENCE-JONES' PROTEIN. 305 



peculiar properties is found in the urine. It is named 

 after Bence-Jones, who first described the condition. It 

 has the property of coagulating at temperatures under 

 55 C., of redissolving to a clear solution on boiling and 

 of reappearing on cooling. It is precipitated by half- 

 saturation with ammonium sulphate. It is not precipi- 

 tated on dialysis. 



Hopkins has shewn that the solution of the heat 

 coagulum on boiling depends on the presence of neutral 

 salts, those with divalent cations (as CaCl 2 ) being most 

 potent in neutral or faintly acid solutions, and those with 

 divalent anions (as K 2 SO 4 ) in faintly alkaline solutions. 



Hopkins has also shewn that the protein excreted is 

 formed in the body, either in the marrow or as a result of 

 the influence of the growth on general metabolism. The 

 amount in the urine is independent of the nature or amount 

 of the proteins of the food. The nitrogen of the protein 

 excreted may be as high as one-third of the total urinary 

 nitrogen. 



373. If necessary make the suspected urine faintly acid with 

 acetic acid. Heat carefully by immersing in a beaker of warm 

 water. The urine becomes turbid at 40 to 45 C., and shows a 

 flocculent precipitate at 60 C. On raising the temperature to iooC. 

 the precipitate partially or completely disappears. On cooling it 

 reappears. 



4. Blood Pigments. 



Blood pigments may occur in pathological urine in 

 intact corpuscles ("haematuria") or free in solution 

 (' ' haemoglobinuria "). 



Haematuria can be recognised by determining the 

 presence of red corpuscles by a microscopic examination 

 of the sediment obtained by centrifugalising the urine. 

 It occurs with gross lesions of the kidney or ^ay part 

 of the urinary tract, so that blood passes directly into the 

 urine. If the blood comes from the kidney it is well 

 mixed with the urine. If the blood comes from the bladder 



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