COLOURING MATTER OF SULPHUR BACTERL4 235 

 Spectra. 



Bacteriochlorin. — Solution in absolute alcohol : 



^^^. , , 1 n • 1 rAbsorption at red end from 65A. 



With coloured fluid . , . 



... J ,, ., violet ,, 52'5A. 



4 mm. thick U 1 , , ; , ^ ^ 



I Dark band, 61A-57A. 



Absorption at red end^ 



With coloured fluid 



i 



10 mm. thick 



from 65A 

 Absorption at violet end 



from 5 3 -5 A 

 Dark band 6r5A-56"5A 



big- 65, III. 



Bacteriopurpurin. — Molisch distinguishes two purple pig- 

 ments : 



Bacteriopurpurin a. — Solution in chloroform : 



With coloured fluid fBand I. 56A-SSA 1 t^. ^ ttt 

 \ J JO \Y\g. 6s IV. 



10 mm. thick iBand II. 52A-48-5AJ " 



Bacteriopurpurin. ^. — Solution in carbon bisulphide : 

 With coloured fluid (Band I. 56A-53-5A. 

 8 mm. thick iBand II. 51A-49A. 



Solution in chloroform : 

 With coloured fluid fBand I. 53A-51A. 

 2 mm. thick iBand If. 50A-48A. 



With concentrated solutions Molisch found what appeared 

 to be a third band, but he was not certain of the fact. 



He obtained crystals of bacteriopurpurin with the following 

 properties : — 



1. Insoluble in water and in glycerine. 



2. Slightly soluble in cold absolute alcohol. 



3. Insoluble in cold, soluble in hot, glacial acetic acid. 



4. Blue to violet colour in pure sulphuric acid. 



5. Blue in concentrated nitric acid. 



6. Dirty green in iodine and potassium iodide solution. 



7. First blue then colourless in strong bromine water. 

 From these facts he concludes that bacteriopurpurin, as 



defined by him, is identical with carotin, using this term in a 

 general sense to cover all the carotinoid pigments. 



