302 PHYSIOLOGICAL CHEMISTRY 



of saturated ammonium sulphate solution. Globulin, if pres- 

 ent, will be thrown down. If the urine is rich in urates they 

 may be precipitated but may be recognized with the microscope 

 or by the murexid test. 



(b) To a few cubic centimeters of clear urine, add an excess 

 of solid magnesium sulphate. Shake thoroughly and globu- 

 lins, if present, will be precipitated and will be deposited above 

 the excess of salt. 



(c) Add a few drops of clear urine to a large beaker full 

 of distilled water. If globulins are present, a white cloud will 

 appear. 



b. NUCLEOPROTEIN. 



After ascertaining that the clear urine does not coagulate 

 upon heating, dilute a small amount with water in equal quan- 

 tities, to prevent the precipitation of uric acid and to reduce 

 the solvent action of the salts upon the nucleoprotein. Add 

 acetic acid drop by drop. Nucleoprotein, if present, will be pre- 

 cipitated. 



Nucleoproteins often are present in large quantities in 

 various forms of proteinuria, such as physiologic proteinuria 

 (occurring at times in healthy individuals after excessive exer- 

 tion, etc.), orthostatic proteinuria (a form in which the pro- 

 tein disappears from the urine if the patient is kept lying 

 down), and lordotic proteinuria (a form accompanying lordo- 

 sis, a variety of spinal curvature). 



It should be borne in mind, however, that the nucleoprotein 

 may have its origin from disintegrated cells, which may be 

 present in large amount. 



c. METAPROTEIN. 



The proteins present in the urine, may be converted, by acids 

 or alkali present, into the metaproteins. Ascertain the chem- 

 ical reaction of urine and neutralize clear urine carefully. If 

 precipitation occurs, heat; the derived albumin will be coagu- 

 lated and will not redissolve on adding acid or alkali. 



