Power of Crystalline Ovalbumin and Serum Albumin. 27 



(3) twice with absolute ether. The precipitate was next transferred to 

 soxhlet thimbles, placed in a desiccator, and transported to the soxhlet 

 apparatus. In this it was now extracted with absolute ether for 15 hours, 

 after which there was no further loss in weight. The thimbles were quickly 

 removed to a desiccator containing H 2 S0 4 and thoroughly dried in vacuo. 

 On cooling, cholesterol esters crystallise out from the ether used in 

 'extraction. The latter apparently extracts some pigment as well, for it 

 becomes coloured a bright yellow. The product obtained by this procedure 

 is a very fine snow-white powder, which can be kept indefinitely if 

 thoroughly dried. It is necessary to keep the precipitate well protected 

 from moist air when in contact with either alcohol or ether at a tem- 

 perature above 0° C. The precipitate will otherwise turn into a brown, 

 brittle mass on drying, which is insoluble in water. From 3250 c.c. of 

 serum, 240 grm. of protein were obtained, representing approximately 

 7'4 per cent : — 



Analysis of Material. 



The white powder in dry form, or as a concentrated solution from which the 

 protein had been removed by means of dialysed iron, was examined for the 

 following substances by the tests mentioned below with negative results in 

 every case. 



(1) Cholesterol by Salkowski and Libermann-Burehard. 



(2) Lipoid by organic phosphorus, choline and sulphuric acid. 



(3) Fat by acrolein. 



(4) Protein hydrolytic products by biuret. 



(5) Glucose by Benedict's picric acid. 



The powder was analysed for total non-volatile solids and for its ash- 

 content by heating to constant weight in a platinum crucible and igniting at 

 a low temperature. The average for three determinations of loss in weight, 

 probably representing volatilisation of traces of alcohol and ether, was 

 12'36 per cent, and of ash T34 per cent, on the dry weight. The samples of 

 powder remained soluble in water in spite of having been subjected to a 

 temperature of 112° for 8 hours. This was no doubt due to the thorough 

 dehydration. 



By reason of the statement made by Hardy and Gardiner that the product 

 obtained by them from horse serum after a somewhat similar procedure showed 

 the normal alkalinity of serum, which, they remark, is not due therefore 

 simply to alkaline carbonates, it was deemed important to determine the 

 alkalinity of the powder in solution. A solution of 13'9 per cent, strength 

 was placed in a hydrogen electrode vessel of the Barendrecht type, installed 



