TOTAL PROTEIDS. 31 



ately determined, employing phenolphthalein as an 

 indicator. 



Acid Potassium Sulfate Mixture. One part of 

 pure potassium sulfate is heated with two parts 

 of sulfuric acid (strictly C. P.) until the potassium 

 sulfate is dissolved. The mixture is semi-solid when 

 cold but may be readily liquified by warming. 



Sodium Hydroxid Solution. A saturated solution 

 in water. The best grades of pulverized caustic soda 

 will suffice, such as those sold as concentrated lye for 

 household use, e.g. "Banner Lye" and that of the Green- 

 bank Alkali Co. 



Digestion Flask. A round-bottomed short-necked 

 flask with a capacity of 300 c. c. 



Distilling Flask. A flask of ordinary shape, about 

 550 c. c. capacity, is fitted by means of a rubber stopper 

 with a delivery tube, the lower end of which projects 

 slightly below the stopper and should be cut off oblique- 

 ly. The tube should be of the same diameter as that of 

 the condensing tube noted below and should have one or 

 two bulbs about four centimeters in diameter to prevent 

 the carrying over of sodium hydroxid during the dis- 

 tillation. 



Copper flasks are now manufactured for this pur- 

 pose and will be found convenient and economical. 



Condenser. The condensing tube must be of block 

 tin of an external diameter of about one centimeter. 

 At least 30 centimeters of its length should be in con- 

 tact with the cooling water. The junction of the glass 



