19 

 VI. 



EXAMINATION OF A TEST SOLUTION FOR PROTEIDS AND 

 CARBOHYDRATES. 



71. Physical characters. 



a. Note color and transparency. 



b. Taste. 



c. Smell. 



d. A persistent froth suggests an albuminous solution. 



72. Divide the fluid into two portions, using one for the 

 proteid and the other for the carbohydrate tests. 



Test for proteids by xanthoproteic and Millon's tests. If 

 present : 



73. Test reaction to litmus paper. If acid or alkaline, 

 test for acid or alkali-albumin, and if either be present, neu- 

 tralize and filter off precipitate. 



74. If original solution be neutral, acidulate faintly and 

 boil. A coagulum may consist of native albumin or globu- 

 lin, or both. 



75. Distinguish between albumin and globulin by (a) 

 dropping solution into water, precipitate indicates globulin ; 

 (b) .saturating solution with magnesium sulphate, precipitate 

 indicates globulin. If precipitate obtained by (b), filter and 

 boil filtrate, coagulum indicates native albumin. Distinguish 

 between egg and serum-albumin by ether test (a non-alka- 

 line solution of egg albumin is coagulated by ether, serum 

 albumin is not). 



76. Gelatin (albuminoid) gives xanthoproteic and 

 Millon's reactions, also a violet color with caustic potash and 

 copper sulphate. It is not coagulated by boiling and is not 

 precipitated by acetic acid and potassium ferrocyanide. 



77. Test for Carbohydrates. 



First remove derived albumins by neutralizing and filter- 

 ing and native albumin and globulin by boiling and filtering. 

 Acidulate if necessary and add iodine. 



