248 THE INCOME OF ENERGY 



ing solutions : l (1) Egg-albumin, (2) Myosin, (3) 

 Alkali-albumin, (4) Peptones. Suspend the egg- 

 albumin and the peptone in vessels containing 

 one litre of normal saline solution (0.8 per cent 

 sodium chloride) ; the alkali-albumin in one litre 



1 Preparation of egg-albumin. Thoroughly mix the whites 

 of twelve or more eggs with saturated solution of magnesium 

 sulphate at 20 C. Filter from the precipitated globulin. 

 Saturate the filtrate at 20 C. with sodium sulphate. Filter 

 the precipitated albumin. Press in filter paper. Dissolve in 

 water. Dialyse until the dialysate is free from sulphates. 

 (Starke, quoted by Hammarsten : Lehrbuch der physiologischen 

 Cheinie, 1897, p. 372.) Determine the albumin in a measured 

 quantity of the solution, as follows. 



Quantitative Estimation of Egg-albumin. To 25 c.c. of the 

 albuminous liquid add an equal quantity of 4 per cent sodium 

 chloride solution. Neutralize exactly. Boil 5 c.c. of this mix- 

 ture in a test-tube. To the boiling liquid add one drop of acetic 

 acid from a burette. Filter from the precipitated proteid. Pour 

 the filtrate carefully down the side of a conical glass containing 

 about 5 c.c. concentrated nitric acid, so that the lighter liquid 

 rests on the heavier acid. If the surface of separation remain 

 clear, all the albumin in the 5 c.c. was precipitated by adding 

 to the boiling liquid one drop of acetic acid. If a white ring 

 form, albumin is still present (Heller's test). In this case boil 

 a fresh portion (5 c.c.), add two drops acetic acid, filter, and 

 test the filtrate. Determine in this way how much acetic acid 

 must be added to each 5 c.c. of the albuminous liquid to pre- 

 cipitate all the albumin when the liquid is boiled. Heat 25 c.c. 

 of the remaining portion of the albuminous liquid in a water 

 bath. Add slowly with constant stirring the calculated quan- 

 tity of acetic acid. Heat ten minutes longer. Filter through 

 weighed paper. Test filtrate once more for albumin. If none be 

 present, wash with water, alcohol, and ether,, dry at_ 40, weigh, 



