426 PHYSIOLOGICAL CHEMISTRY 



as in the ordinary coagulation test (page 424), but they may be easily differentiated 

 from albumin by means of their solubility in alcohol. 



GLOBULIN 



Serum globulin is not a constituent of normal urine but frequently 

 occurs in the urine under pathological conditions and is ordinarily 

 associated with serum albumin. In albuminuria globulin in varying 

 amounts often accompanies the albumin, and the clinical significance 

 of the two is very similar. Under certain conditions globulin may occur 

 in the urine unaccompanied by albumin. 



EXPERIMENTS 



Globulin will respond to all the tests just outlined under Albumin. 

 If it is desirable to differentiate between albumin and globulin in any 

 urine the following processes may be employed: 



1. Saturation with Magnesium Sulphate. Place 25 c.c. of neutral urine in 

 a small beaker and add pulverized magnesium sulphate in substance to the point 

 of saturation. If the protein present is globulin it will precipitate at this point. 

 If no precipitate is produced acidify the saturated solution with acetic acid and 

 warm gently. Albumin will be precipitated if present. 



The above procedure may be used to separate globulin and albumin 

 if present in the same urine. To do this filter off the globulin after it 

 has been precipitated by the magnesium sulphate, then acidify the clear 

 solution and warm gently as directed. Note the formation of the 

 albumin precipitate. 



2. Half -saturation with Ammonium Sulphate. Place 25 c.c. of neutral urine 

 in a small beaker and add an equal volume of a saturated solution of ammonium 

 sulphate. Globulin, if present, will be precipitated. If no precipitate forms add 

 ammonium sulphate in substance to the point of saturation. If albumin is present 

 it will be precipitated upon saturation of the solution as just indicated. This 

 method may also be used to separate globulin and albumin when they occur in the 

 same urine. 



Frequently in urine which contains a large amount of urates a precipitate of 

 ammonium urate may occur when the ammonium sulphate solution is added to the 

 urine. This urate precipitate should not be confounded with the precipitate due 

 to globulin. The two precipitates may be differentiated by means of the fact that 

 the urate precipitate ordinarily appears only after the lapse of several minutes 

 whereas the globulin generally precipitates at once. 



PROTEOSE AND PEPTONE 



Proteoses, particularly deutero-proteose and hetero-proteose, have 

 frequently been found in the urine under various pathological con- 

 ditions such as diphtheria, pneumonia, intestinal ulcer, carcinoma, 



