172 Report of the Chemical Department of the 



rubbing- and again dried, after whicli it was extracted with ether 

 to remove fat and then reduced to a finely powdered white mass. 

 This mass was extracted with several portions of water at 122° F. 

 (50° 0, until about 12 liters were collected, the water-soluble 

 contents of the mass having- been thoroughly extracted by this 

 treatment. This extract was precipitated with tannin and filtered; 

 the tannin in the filtrate was removed by lead acetate. The result- 

 ing precipitate of lead tannate was filtered and washed three times 

 by suspension in water and refiltering. The excess of lead was re- 

 moved by sulphuric acid and the last traces by hydrogen sulphide. 

 The filtrate was then carefully concentrated at 55° C. to about 

 4 liters, made acid with 5 per ct. of sulphuric acid and precipitated 

 with phosphotungstic acid. The precipitate was washed with 

 dilute sulphuric acid. The filtrate from the phosphotungstic acid 

 precipitate was examined for tyrosine and the precipitate for 

 oxyphenylethylamine and the hexon bases. 



Tyrosine. — The filtrate from the precipitate by phosphotungs- 

 tic acid was treated with barium oxide to remove the phospho- 

 tungstic acid and the barium hydroxide in the filtrate carefully 

 removed by sulphuric acid. This filtrate was concentrated to a 

 small volume. On standing, crystals separated from the solution 

 having much the appearance of tyrosine. These were filtered, 

 redissolved in water, recrystallized several times from water 

 after concentration of solution and finally washed with alcohol 

 and dried over sulphuric acid /;; vacuo. A nitrogen determina- 

 tion by the Kjeldahl process gave the following results: 



Calculated for tyrosine. Found. 



(C, H„ NC).,) 



N 7.68 per ct. y.yz per ct. 



The substance gave the color reactions that are characteristic 

 of tyrosine and was undoubtedly tyrosine. The separation of 

 other monoamido compounds was not attempted. 



0.vypJicnylcth\Iaininc. — About one-fourth of the phosphotung- 

 r.tic acid precipitate, obtained in the manner previously described, 

 was decomposed by barium oxide and filtered. The excess of 

 barium hydroxide was removed fromi the filtrate by means of 

 carbon dioxide. The clear filtrate was concentrated at a low 



