5 GEORGE V. SESSIONAL PAPER No. 39b A. 1915 



VII. 



THE IODINE CONTENT OF THE MARINE FLORA AND FAUNA IN THE 

 NEIGHBOURHOOD OF NANAIMO, VANCOUVER ISLAND, B.C. 



{With an Appendix on the Economic Value of the Pacific Kelps) 



By a. T. Cameron, M.A., B.Sc, 

 Assistant Professor of Physiology and Physiological Chemistry, University of 



Manitoba. 



The two outstanding facts of biological importance in the history of the 

 element iodine are the discovery of the element by Courtois in sea-weeds, in 1811, 

 and the discovery of its presence in the thyroid gland by Baumann in 1885. Sub- 

 sequent to the latter discovery, most of the biological investigation of the element 

 was directed to discover its function in the thyroid gland. In spite ot a very large 

 number of papers which have appeared during the last twenty years, this function 

 is still obscure. It has been shown with fair certainty that iodine is a constituent 

 of all normal thyroid tissue,^ and that the amount present is dependent on the 

 amount in the diet. I showed recently that iodme is present in the thyroid of the 

 dog-fish Scyllium canicula in amount greater than any previously recorded,^ and 

 this fact suggested the desirability of making comparative determinations of the 

 iodine content of the various forms of sea-life, since the element is known to be 

 present in sea-water, and since here the relative effect of a constant iodine diet 

 should show itself distinctly. 



Iodine is known to be present in most Sea-weeds, and has further been dis- 

 covered in Sponges and Corals. In these two kinds of animals it has been established 

 beyond doubt^ that it is present in organic combination, and at least in part in a 

 protein complex in a radical derived from di-iodo-tyrosine. Definite proof has yet 

 to be adduced of the presence of a similar complex in the thyroid, for though 

 evidence supporting such a hypothesis has been put forward by Oswald and others,* 

 the exact nature of the combination of iodine in Oswald's "thyreoglobulin"* has 

 yet to be determined. I considered that further data as to the amount of iodine 

 present in different kinds of marine organisms, and especially as to the kind of 



* I have summarised the evidence in favour of this view in a paper on "The presence of Iodine 

 in the Thyroid Gland," J. Biol. Chem., 1914, 16, 465. 



' Biochemical J., 1913, 7, 466. 



* See for example, Wheeler and Mendel, /. Biol. Chem., 1909, 7, 1 ; Drechsel, Zeitschr.f. Biol, 

 1896, 33, 85; Morner, Zeitschr.f. physiol. Chem., 1907, 51, 33; 1908, 56, 77, 223. 



* Cp. for example, Oswald, Arch. f. exp. Path. u. Pharm. 1908, 60, 115; Niimberg, Bio chem 

 Zeitschr, 1909, 16, 87. 



* Oswald, ibid., 1901, 32, 121. 



