404 



ON THE OCCURRENCE OF 



In each of these species iodine was found to be a constituent 

 of the horny axial skeleton. The organic material was fused 

 with pure sodium hydroxide and potassium nitrate, and the 

 fusion products were tested for iodine in the usual way by 

 acidification and extraction with chloroform. All the reagents 

 used were previously ascertained to be absolutely free from 

 iodine. In order to afford a quantitative comparison with the 

 specimens examined by Drechsel, the adherent material was 

 carefully separated from portions of the air-dry axial skeletons, 

 and the latter comminuted and dried for analysis at 110 C. 

 After fusion in a nickel crucible with pure sodium hydroxide, 

 the halogens were precipitated as silver salts and determined 

 by the method which Drechsel * employed. In the table of 

 results, the analyses of Gorgonia cavolinii are added for 

 comparison.! 



SUMMARY OF THE ANALYSES. 



While the results presented are considerably smaller than 

 the figures obtained for Gorgonia cavolinii, they compare more 

 closely with the published analyses of certain algae $ (Fucus 

 vesiculosus, Laminaria digitata) and with Harnack's determi- 

 nations of the iodine content (1.5 per cent) of ordinary 

 sponges. It is suggestive to note that the species of West 

 Indian coral richest in iodine is the one most closely related to 

 the Mediterranean Gorgonia cavolinii. 



In his monograph on " The physiological r6le of mineral 



* Drechsel, Zeitschrift fur Biologic, 1896, xxxiii, p. 96. 



t Most of these analyses were made by A. N. Richards, B. A. 



} Eschle, loc. cit. 



Harnack, loc. cit. p. 414. 



