LUTEINE. 



145 



2. Reactions of the juice. 



a. Add nitric acid ; a precipitate, pink at first, 

 afterwards greenish-yellow, appears. 



b. Add sulphuric acid; a precipitate will be 

 formed, which will redissolve and turn red- 

 dish-brown. 



c. Add sulphuric acid and a little sugar; a 

 fine purple colour will be produced, showing 

 in the spectroscope one band in green. 



A aBC 



Eb 



HH' 



spectrum of juice of corpora lutea treated with sulphuric acid. 



d Add hydrochloric acid ; no reaction. 

 3. Reactions of Alcoholic Extract. 



a. Dry the solid residue of the corpora, extract two 

 or three times with boiling alcohol of 85%, filter 

 hot, allow the mixed extracts to stand in the 

 dark till clear, decant the liquid, and examine 

 as follows : 



b. Add water; a turbidity will be produced, 

 not removable by heating. 



c. Add potash solution ; a yellow precipitate 

 will gradually deposit. 



d. Add mercuric chloride, auric chloride, or pla- 

 tinic chloride ; no reduction will take place. 



e. Add mercuric nitrate ; a copious yellow pre- 

 cipitate will fall, becoming white on heating. 



10 



