268 A. LIVERSIDGE. 



part as haemoglobin in the blood of the vertebrates, i.e. as a 

 carrier of oxygen. It enters the gills colourless, absorbs oxygen 

 and becomes blue, in its passage through the tissues it loses oxygen 

 and again becomes colourless. Hsemocyanin contains copper in 

 place of the iron in haemoglobin. It coagulates at 65° and is 

 precipitated by neutral salts and separated by dialysis. 1 



Emu Egg Shell. — The dark green pigment of this shell gives a 

 beautiful sapphire blue to glacial acetic acid, also to formic and 

 lactic acids. It is a still more beautiful colour than that from 

 the coral. 



Crustacea. — The blue pigment of the lobster and crab becomes 

 red on boiling and by alcohol, but the coral blue does not. 



It is unfortunate that so very little is known about the chemical 

 composition of animal pigments, and this is especially the case with 

 the non-crystallisable ones. In these notes I have only drawn 

 attention to such of the animal pigments as appear to be at all 

 allied to the blue coral pigment. 



From the foregoing it will be seen that the blue pigment from 

 this coral appears to differ more or less from all of the other 

 animal blues referred to, including the bile pigments, but before it 

 can be definitely stated to be a distinct substance, both this pig- 

 ment and many of the others require to be further examined. 



I am expecting to receive a further supply of the Heliopora 

 coerulea when I hope to be able to obtain the pigment free from 

 extraneous nitrogenous and other impurities. The pigment (or 

 its accompanying impurities) apparently contains unoxidised 

 sulphur. 



1 Haliburton — Journ. Physiol., vi., 300. 



