BLUE PIGMENT IN CORAL AND OTHER ANIMAL ORGANISMS. 257 



corallum the continuation of the dark blue line marking the 

 margin of the wall of each tube enables the line of the tube to be 

 traced past the superadded tabula, and marks the boundary 

 between the two structures. Very exceptionally, intensely blue 

 streaks are developed more internally on either side of the central 

 canal. The tabulae are almost colourless." 



Separation of the Pigment. 



On shaking the finely powdered coral with water, the blue 

 pigment does not float, as might have been anticipated, but rather 

 tends to collect at the bottom of the vessel; not sufficiently how- 

 ever to be used as a means of separating and collecting it. 



As stated by Moseley the readiest way to separate the pigment 

 from the mineral matter of the coral is to dissolve the coral in 

 hydrochloric acid, when the blue colouring matter mixed with 

 animal matter is left in suspension, it can then be filtered off 

 from the calcium chloride solution, which passes through the filter 

 in a colourless condition. 



Some of the pieces of coral were old and waterworn, "dead" 

 coral : — a specimen of this dissolved in pure hydrochloric acid left 

 a small quantity of insoluble residue amounting to about "2%; 

 under the microscope this was seen to consist of rock debris, 

 probably pumice, and a few crystals and groups of crystals of 

 magnetite. 



One specimen of such " dead " coral yielded "267% of the crude 

 pigment after drying in a water oven. A specimen of the unrolled, 

 or "live" coral yielded 1*123% of the dried pigment, the greater 

 yield from the "live" coral appears to be due to the larger 

 amount of animal matter mixed with the pigment. 



The crude pigment as set free from the coral by hydrochloric 

 acid is black in colour, and on drying splits up into small pieces 

 with very lustrous conchoidal surfaces, and it is exceedingly 

 tender and so brittle that on crushing much of it flies out of the 

 mortar. 



Q— Dec. 7, 1898. 



