220 Capsulcs of Shark Eggs [Dec 



Pigments from egg capsules of the Port Jackson shark. The 

 coloring matter of the Heterodontns tgg capsules was prepared in a 

 manner similar to that employed for the isolation of the Raja 

 product, the only difference being that a lo per cent. hydrochloric 

 acid Solution was employed, instead of a 5 per cent. potassium 

 hydroxide Solution. The acid medium was carefully neutralized 

 with potassium hydroxide. The neutralization precipitate was 

 filtered off^^ and the filtrate dialyzed. The salt-free Solution was 

 evaporated spontaneously to dryness. 



The pigment scales thus obtained were almost colorless. They 

 were soluble in water, in alkali, and in acid (more readily than in 

 alkali). In 10 per cent. hydrochloric acid Solution, the pigment 

 yields a Solution, which, on shaking, becomes frothy like an aqueous 

 protein Solution. This Solution is light orange in color. The color 

 of the neutral Solution of this pigment is similar to that of the acid 

 Solution. The alkaline Solution is brownish-yellow in color. The 

 Solutions of this pigment are much less delicately responsive to 

 changes in the reaction, than are those of the pigment from the 

 skate capsules. The pigment is insoluble in both hot and cold 

 alcohol (95 per cent.), and in ether and Chloroform. 



Each of the coloring matters of these capsules gave evidence of 

 the presence of nitrogen by the Lassaigne test. The xanthopro- 

 teic, Millon, and Hopkins-Cole tests were positive with both of the 

 coloring materials. The colored Solution interfered with the biuret 

 test in such a way as to make the result doubtful. 



On the natura of the neutralization precipitate from the 



pigment extracts. Neutralization of the pigmentary extracts 



of the capsular material yielded, in each case, a grayish floc- 



culent precipitate which was isolated by filtration. The precipitate 



was washed with water and redissolved in 5 per cent. potassium 



hydroxide Solution. The Solution was filtered and then neutralized. 



The reprecipitated matter was again filtered off and the precipitate 



thoroughly washed. The precipitate in each case responded posi- 



tively to the Millon, xanthoproteic and Hopkins-Cole tests. That 



this substance is protein, in whole or in part, is obvious. It appears 



to be metaprotein. 



"The further treatment of this precipitate is described under the next sub- 

 heading. 



