78 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. 



spectroscopically for me by Dr. Alfred Holt, Eeader in 

 Physical Chemistry in the University, and he has shown 

 me that the pigment is not chlorophyll — as might 

 have been supposed at first — but has a characteristic 

 absorption band in the orange, intermediate in position 

 between the band given by sodium and ^ that of 

 chlorophyll. The position of this band in Angstrom 

 units is 6200; while chlorophyll gives a band at 6550, 

 and "bonelleine," described by Sorby in 1875 from the 

 green Gephyrean worm Bonellia viridis, has the band at 

 6430. The Syntethys pigment, however, does not go 

 purple with acids and therefore cannot be bonelleine. 

 Acids or alkalies turn it somewhat yellowish, and the 

 colour is not restored on neutralisation. No distinct 



Syntethine 



Chlorophyll. 



Bonelleine. 



Fig. 21. 



bands are shown in acid or alkaline solutions. Possibly 

 our substance and bonelleine belong to the same natural 

 group of pigments. Dr. Holt has kindly supplied the 

 diagram (fig. 21) showing the spectrum of the new 

 pigment — to which the name "syntethine" may be 

 applied — compared with those of bonelleine and of 

 chlorophyll. 



It is remarkable to find that the violet-coloured 

 preserved Syntethys still continues to give out the green 



