438 SCIENCE PROGRESS 



water ; a colloidal solution is thereby obtained : from this ether 

 extracts carotin, but not chlorophyll. After this extraction, 

 calcium chloride was added to the colloidal solution ; after this 

 addition the chlorophyll was readily dissolved by ether. The 

 crude chlorophyll prepared from various sources by these 

 methods contained in some cases no phosphorus at all, and in 

 others from 0*0117 to 0*44 per cent.; the magnesium content, 

 however, was generally about 1 per cent. 



Attempts were also made to prepare the first and least changed 

 derivative obtained from chlorophyll by the action of alkali. It 

 was found that by the action of alcoholic potassium hydroxide 

 in the cold a product was obtained which contained only 7 per 

 cent, of nitrogen, whereas the alkachlorophyll of Schunck and 

 Marchlewski contained more than 11 per cent. The substance 

 prepared by the action of cold alcoholic caustic alkali solu- 

 tions was designated chlorophyllin. (This name was originally 

 suggested by Timiriazefif.) It was prepared by adding a methyl- 

 alcoholic solution of potassium hydroxide to an alcoholic double 

 extract of leaves, dissolving the salt which separated out, in 

 water, and extracting the aqueous solution with ether. By this 

 means, impurities such as carotin, which accompany the potassium 

 salt, could be separated, the sodium salt of the acidic chlorophyllin 

 remaining in the aqueous solution. From this it can be obtained 

 by just neutralising with phosphoric acid, then acidifying with 

 dihydrogen sodium phosphate, which decomposes the sodium 

 salt, but does not remove the magnesium, and then extracting 

 the mixture with ether. The product can be further purified by 

 extracting the ethereal solution with ;;/o;/ohydrogen ^/sodium 

 phosphate, which is sufficiently alkaline to extract the acidic 

 chlorophyllin ; some of the accompanying impurities remain in 

 the ethereal solution. On adding the ^/hydrogen monosodium 

 phosphate to the aqueous solution, the chlorophyllin is again set 

 free from its sodium salt and can be extracted with ether. In 

 this way a somewhat weakly acid product was obtained from 

 several varieties of plants, which was non-crystalline in character 

 and which invariably contained magnesium in quantities of from 

 2-3 to 3'5 per cent., which could be readily eliminated from the 

 molecule by the action of weak acids. 



Phceophytin and Phytol. — After having investigated the gentle 

 action of alkalis on chlorophyll extracts attention was turned 

 to the gentle action of acids, and it was found that the first 



