400 PHYSIOLOGICAL CHEMISTRY. 



constantly and heating at the same time. Filter while warm, 

 wash first with water, then with alcohol and ether, dry and weigh, 

 ash. and weigh again. In exact determinations the filtrate must 

 not give HELLER'S test. 



The separate estimation of GLOBULINS and ALBUMINS is done 

 by carefully neutralizing the urine and precipitating nvith MgS0 4 

 added to saturation (AUTHOR), or simply by adding an equal 

 volume of a saturated neutral solution of ammonium sulphate 

 (HOFMEISTER and POHL). The precipitate consisting of globulin 

 is thoroughly washed with a saturated magnesium sulphate or half- 

 saturated ammonium-sulphate solution, dried continuously at 110 

 0., boiled with water, extracted with alcohol and ether, then dried, 

 weighed, ashed, and weighed again. The quantity of albumin is 

 calculated as the difference between the quantity of globulins and 

 the total proteids. 



Approximate Estimation of Albumin in Urine. Of the methods 

 suggested for this purpose none has been more extensively employed 

 than ESBACH'S. 



ESBACH'S method. The acidified urine (acidified with acetic 

 acid) is poured into a specially-graduated tube to a certain mark 

 and then the reagent (a 2$ citric-acid and \% picric-acid solution 

 in water) is added to a second mark, the tube is closed with a 

 rubber stopper and carefully shaken, avoiding the production of 

 froth. The tube is allowed to stand twenty-four hours, and then 

 the height of the precipitate in the graduated tube is read off. 

 The reading gives directly the quantity of albumin in 1000 parts of 

 the urine. Urines rich in albumin must first be diluted with water. 

 The results obtained by this method are, however, dependent upon 

 jthe temperature; and a difference in temperature of 5 to 6.5 C. 

 may in urines containing a medium quantity of albumin cause an 

 error of 0.2-0.3$ deficiency or excess (CHRISTENSEN and MYGGE). 

 This method is only to be used in a room in which the temperature 

 may be kept nearly constant. The directions for the use of the 

 apparatus accompany it. 



CHRISTENSEN'S and MYGGE'S method. 5 c. c. of urine, after 

 being acidified with 2 drops of acetie acid, are poured into a some- 

 what modified burette and precipitated with a certain quantity of 

 a \% tannic-acid solution and then treated with 1 c. c. of mucilage. 

 After the addition of water to a certain mark and after inverting 

 the tube several times a uniform emulsion is produced. A cylin- 

 drical glass filled one half or one third with water is now placed on 

 a white surface having a number of close black lines traced upon it, 

 and the contents of the burette are gradually added to the water 

 with constant stirring, until by close observation the black lines 

 cannot even be distinguished from the white spaces. The reading 

 of the amount of urine emulsion employed gives directly the 



