ESTIMATION OF ALBUMIN 



189 



If milk has been treated with an excess of hydrogen peroxide 

 or heated with a smaller quantity of this substance, the perox- 

 idases are destroyed and a negative reaction is obtained with 

 the usual reagents. Formaldehyde, in the quantities usually 

 employed for milk preservation, has no apparent effect on the 

 Schardinger test. 



Estimation of Albumin. The estimation is most readily 

 performed in the manner described on page 74. 



Rupp 1 obtained the following results with heated milk. 



Milk Heated for Thirty 

 Minutes at 



Percentage of Albumin 

 Precipitated. 



62.8 C. (145 F.) Nil 



65.6 C. (150 F.) 5.75 



68.3 C. (155 F.) 12.75 



71.1C. (160 F.) 30.87 



The rennin coagulation may also be used for the detection 

 of sterilised milk or milk heated at temperatures exceeding 

 65 C. Rupp's results (vide supra) in this connection are 

 given in Table LXIV. 



TABLE LXIV 



Time required for rennin coagulation of raw and heated 

 milk. Milk 200 c.cms. : rennin solution (0.15; 100 c.cms. water) 

 5 c.cms. 



