434 SCIENCE PROGRESS 



cent, solution. The mixture was heated for a quarter of an hour 

 with a reflux condenser and diluted with water, neutralised 

 with hydrochloric acid, and extracted with ether ; the ethereal 

 solution was then freed from alcohol by repeated washing 

 with water. The ethereal solution was then extracted with 

 17 per cent, hydrochloric acid, and in this way the very weak 

 bases and indifferent substances separated from the main 

 products of the reaction. The hydrochloric acid extract was 

 then diluted with water, so as to have an acid content of 

 1 3 per cent., and extracted with ether to separate the last portions 

 of the weak bases. The acid solution was then neutralised and 

 extracted with ether, and a solution was obtained which contained 

 two chief products, designated phytochlorin a, and phytochlorin b. 

 The ethereal solution was then extracted several times with 

 3 per cent, hydrochloric acid, which is just strong enough to 

 extract the more basic product phytochlorin b, whilst the less 

 basic product remained in solution. On neutralising the 3 per 

 cent, acid solution and extracting with ether, the product phyto- 

 chlorin b was obtained nearly pure. The original ethereal 

 solution, after the extraction of the phytochlorin b, was then 

 shaken with 4I per cent, hydrochloric acid solution ; this was 

 not quite strong enough to extract the weaker base phytochlorin a, 

 but sufficient to wash out the last traces of the product b. 

 The ethereal solution was then extracted with 6 per cent, acid, 

 which extracted fully the weaker base. By the repetition of 

 this extraction, i.e. by extraction of the ethereal solution of 

 phytochlorin b, with 3! per cent, acid, and of phytochlorin a 

 with 6 per cent, acid after a previous extraction with 4! per cent 

 acid, the two products could be obtained pure. 



By dissolving phytochlorin a in concentrated alcoholic 

 potassium hydroxide, and heating the solution thus obtained for 

 a short time, it is converted quantitatively into phytochlorin b ; 

 both products, furthermore, undergo change on standing in acid 

 solution, being converted chiefly into a mixture of two other 

 products, designated respectively phytochlorin c and phyto- 

 chlorin d. All these are crystalline products which can be 

 distinguished from one another by differences in the crystalline 

 forms, in the colours of their solutions, and degrees of solubility 

 in organic solvents. Their chief properties are summarised in 

 the accompanying- table (Table I.). 



