28 Mr. E. G. Young. On the Optical Rotatory 



in a constant temperature chamber at 18°, connected up with a calomel 

 electrode containing saturated KC1 solution and the usual electrical appliances 

 for the electrometric determination of hydrogen ion concentration. The 

 Walpole medical research potentiometer was used with a Weston standard 

 cell as standard. The E.M.F. observed was 689 - 5 millivolts which represents 

 a hydrogen ion concentration of 2-45 x 10" 8 or P H 7'61. The solution was 

 next diluted with an equal volume of water and the difference of potential 

 again determined. The result was the same as before. 



As the ash-content of the protein powder is quite appreciable, and as is 

 evident from the experiments recorded below this ash is made up, at least in 

 part, of fixed alkali, the alkalinity of the solution I would attribute to the 

 inorganic constituents rather than to the weakly basic protein. 



In the following experiments on the albumin obtained by the above method 

 the determinations of Ph were made by the potentiometric method as used for 

 the alkalinity determination. 



Experiment 1. — A 20 per cent, solution was prepared in distilled water. It 

 may be noted here that in spite of its content of globulin the protein powder 

 is entirely soluble in distilled water. It would thus appear that by this 

 method of preparation the eu-globulin is so changed that it is now quite 

 soluble in distilled water. To the mixed protein solution was added a 

 saturated solution of Kahlbaum's purest (NH^SO* in equal volume. As is 

 the case with ovalbumin preparations a distinct odour of ammonia is per- 

 ceptible, indicating the presence of fixed alkali. The Ph of the medium was 

 5"84. The globulin precipitate was allowed to settle for 24 hours. It was 

 then filtered off and a portion of the filtrate made acid with acetic acid 

 (10 per cent.) to the point of equilibrium found desirable in the crystallisa- 

 tion of ovalbumin, i.e. a slight permanent precipitate. No crystals were 

 formed and the solution had a Ph of 4 - 16. Another portion of the filtrate 

 was similarly treated with acid but to a less degree. Crystals appeared in 

 12 hours. The Ph of the mother liquor was 4"30. The remaining filtrate 

 was treated with acid to a point when the first faint turbidity was visible. 

 Crystals in abundance were deposited inside of an hour. The Ph of the 

 mother liquor was 4'54. The angles of the crystals were sharp and the 

 crystals themselves large and single, resembling small hippuric acid crystals 

 very closely. They were filtered off and dissolved in distilled water. There 

 was absolutely no trace of residue remaining in the fluid. The solution was 

 coloured a yellowish-brown. An attempt to recrystallise this preparation by 

 addition of saturated (NH4) 2 S0 4 solution, added to the point of the first 

 permanent turbidity, produced not a single crystal but only a bulky 

 amorphous precipitate in about 30 minutes. 



