6 U. S. BUREAU OP FISHERIES 



Table 5. — Iodine content of fresh substance of foods and some other plant and 

 animal products as determined by von Fellenberg — Continued 



Kind of food 



Water animals: 



Trout 



Pcrcii 



Sardines, market " Amleux" headless. 



Tuna -- 



Bath sponge 



Fats and oils: 



Peanut oil 



Lard 



Cod-liver oil- 

 Refined 



Crude 



Beverages: 



Wine 



Fruit wine, pear and apple 



Cherry mash 



Source 



Bern market... 



do 



Mediterranean. 



do 



Greece 



Scandinavia. 

 do 



Canton Tessin... 

 Canton Thurgau. 



Mg. Iper 

 kilogram 



.036 

 .029 

 .163 

 .053 

 3, 870. 000 



.004 

 .017 



7.200 

 3.370 



.013 

 .008 

 .002 



Parts 



per 



billion 



36 

 29 

 163 

 53 

 3, 870, 000 



4 

 17 



7,200 

 3,370 



13 

 8 

 2 



Table 6. — Iodine content of parts of fishes, as determined by von Fellenberg 



' Not demonstrable. 

 • Not determined. 



EXPERIMENTAL 



THE METHOD 



Von Fellenberg's extraction method (1923) was used in determin-. 

 ing the iodine content of fish, mollusks, and crustaceans. The 

 procedure was modified so as to be especially adapted for fish. A 

 detailed description of the procedure follows. 



Fifty to 100-gram samples of the finely chopped material were 

 weighed into silica or porcelain evaporating dishes and heated in a 

 drying oven at 105° centigrade to constant weight. The dried 

 samples were ground in a mortar with 3 grams of calcium oxide and 

 returned to the dishes. Three cubic centimeters of a satmated 

 solution of potassium carbonate and sufficient water to make a 

 thick paste were then added. The samples were then heated on a 

 hot plate, slowly at first, and more rapidly after the water had been 

 evaporated. After carbonation was complete, the dishes were 

 heated to dull redness until all the carbon had been oxidized. After 

 cooling, the ignited samples were covered with water and then 

 heated until the water boiled. The resulting solution was decanted 

 through a filter and the residue rubbed to pieces with a stirring rod. 

 The extraction with boiling water was repeated five or six times. 

 The resultant filtrate was evaporated to dryness. In order to sepa- 



