MEDICINAL EFFECTS OF FISH. 267 



" I may briefly mention, that in every instance in 

 which I have sought for this substance in sea-fish, I 

 have found distinct traces of it, and also, though not 

 so strongly marked, in the migratory fish, but not in 

 fresh-water fish. The trials I have made have been 

 limited to the following : viz., the Eed Gurnet, 

 Mackerel, Haddock, Common Cod, Whiting, Sole, 

 Ling, Herring, Pilchard, Salmon, Sea-Trout, Smelt, 

 and Trout. In the instance of the fresh-run Salmon, 

 Sea-Trout and Smelt, a slight trace of iodine was de- 

 tected; in the spent Salmon descending to the sea, 

 only a just perceptible trace of it was observable, and 

 not a trace of it either in the Parr or in the Trout. 



" That iodine should enter into the composition of 

 sea-fish, is no more perhaps than might be expected, 

 considering that it forms a part of so many of the 

 inhabitants of the sea on which fish feed ; to mention 

 only what I have ascertained myself, in the common 

 Shrimp I have detected it in an unmistakable manner, 

 and also in the Lobster and Crab ; and likewise in the 

 Common Cockle, Mussel, and Oyster." 



Dr. Pereira, in his treatise "On Food and Diet," 

 says iodine has been found in the Mediterranean Sea, 

 by Balard.* Professor Liebig also includes iodides in 

 his analysis of sea-water, t Sea-weed and sponge con- 

 tain iodine, and are used medicinally on that account. 

 Iodine, in combination, was detected in cod-liver oil by 

 Herberger.J 



* P. 105. 



t " Chemistry in its application to Agriculture and Physiology," 

 p. 110, 2nd Edit. J Pereira on Food and Diet, p. 287. 



