14 



Prof. A. J. Ewart. 



that chlorophyll in the presence of the enzyme chlorophyllase and of 

 ethylic alcohol forms methyl ethyl chlorophyllide or crystalline chlorophyll 

 and the alcohol of phytyl (phytol) 



COOH .COOH 

 C 3 iH a9 N 4 Mgf COOOHg +C 2 H 5 OH = C 31 H 29 N 4 Mgf COOCH 3 +C 20 H 39 OH. 

 X COOC 20 H 39 x COOC 2 H 5 



The same enzyme appears also to be able to produce the synthesis of chloro- 

 phyll from phytol and methyl ethyl chlorophyllide. 



In any case, the phytyl radicle of chlorophyll is easily displaced, and there 

 appears to be some evidence that the chlorophyll may be re-formed from 

 xanthophyll and the colourless waxy residues of bleached chlorophyll. 

 Thus, if in the first separation of chlorophyll a slight excess of water is 

 added and the liquid kept in darkness in a separating funnel for one or 

 more days, at the top is impure petrol ether chlorophyll, on the surface 

 of the watery layer is an emulsion containing chlorophyll, impurities, 

 and solid carotin, well below this the liquid is yellow with a white 

 turbidity (A) and at the bottom is a clear yellow liquid (B). If B is 

 evaporated to dryness and digested with cold alcohol, it yields xanthophyll. 

 If an equal volume of A is run off, no chlorophyll can be extracted from 

 it by petrol ether, or detected in it by the spectroscope. On evaporating 

 it (in very feeble light), when nearly all the alcohol has been driven oil', 

 green skins of chlorophyll form. On filtering, the liquid is brown but 

 turbid and again forms fresh chlorophyll on evaporating. If filtered as 

 often as any green pigment separates, the ultimate dry residue may contain 

 little or no xanthophyll as compared with the residue from B. The amount 

 of chlorophyll recovered in this way may be sufficient to tinge the original 

 volume quite green, and to mask the yellow colour when dissolved in 

 alcohol and added to a fresh portion of the original liquid. 



A large number of attempts were made to obtain chlorophyll from the 

 colourless products of its oxidation and xanthophyll or carotin. In one 

 experiment freshly bleached chlorophyll dissolved in hot alcohol was poured 

 into water, the alcohol partially evaporated, and a watery solution of 

 xanthophyll added. A little zinc dust was added, and the tube was sealed 

 so as to enclose half its volume of air, so that on exposure to diffuse 

 daylight oxidation took place at the surface, reduction at the bottom. After 

 three days, on opening, partially evaporating, adding alcohol, filtering, and 

 then adding first petrol ether and then water, the petrol ether showed a 

 distinct green colour and red fluorescence and the spectrum of chlorophyll, 

 although no chlorophyll was present originally. This result was, however, 

 quite capricious. Out of some 20 experiments about three in four were 



