Oxidation of Xanthophyll. 185 



The watery liquid was then evaporated to dryness and the brown, 

 gummy residue digested with a small quantity of cold water and 

 filtered. The clear brown filtrate has a slightly sweetish taste, fol- 

 lowed by the bitter flavour of wax impurities. If the digestion 

 is prolonged in a larger quantity of water, the whole residue breaks 

 up, and the less soluble portion swells to form a colloidal solid 

 which is difficult to separate by filtering. It can, however, be con- 

 densed by the addition of a few drops of lead acetate. 



The filtrate and also the filtrate from the photo-oxidation in 

 water of impure chlorophyll from the first petrol ether separation 

 gave the following tests : — 



1. With a naphthol and sulphuric acid it gave the furfural test 



for carbohydrates (green ring, red above, purple on 

 cooling and shaking). 



2. Warmed with phloioo;lucin and hydrochloric acid, the solu- 



tion deepened slightly in colour, but gave no pink. 

 Hence no pentoses were present. 



3. Strong reduction with Fehling's test not increased by 



previous warming with a drop of sulphuric acid. Hence 

 no cane sugar present, but maltose, glucose or levulose. 



4. With hydrochloric acid and resorcin it gave one warming 



a red liquid and a brown precipitate on standing. 

 Since cane sugar is not present this shows the presence 

 of a keto hexose such as levulose. 



5. Milk of lime was added, and the liquid filtered. 

 Precipitate. — A portion dissolved in HCl. gave a fairly strong 



reduction with Fehling's test. A second portion was neutralised, 

 and phenylhydrazin hydrochloride and sodium acetate added. 

 After warming half an hour on a water bath a finely granular 

 yellow glucosazone precipitate was given = presence of levulose. 



Filtrate gave a blood red with picric acid and sodium hydrate. 



Carbon dioxide was passed into the remainder of the filtrate, 

 which was then evaporated to dryness, water added and refiltered. 

 The filtrate gave a fairly strong reduction with Fehling's test, but 

 not as strong as before the precipitation of the levulose. Presence 

 of glucose. 



In a further experiment, the watery extract from oxidised " xan- 

 thophyll," after clearing and filtering, was treated with ammoni- 

 cal lead acetate and filtered. The precipitate was washed, sus- 

 pended in water, carbon dioxide passed through, and again filtered, 

 The filtrate was evaporated to dryness, dissolved in a minimum of 

 water, and cleared and decolorized with animal charcoal. The 



