92 U. S. BUREAU OF FISHERIES 



was made of the chemical composition of tliis product. This revealed 

 that conch meat, on a fresh basis, contained the following: moisture, 

 74.6 percent; protein, 18.6 percent; fat, 0.3 percent; and ash, 1.7 

 percent. Also it was found that conch meat contains 290 parts of 

 iodine per billion. 



MINERAL CONSTITUENTS OP FISHERY PRODUCTS AND BYPRODUCTS 



Much has been written in the scientific literature in recent years 

 concerning; the increasing imjjortance of minerals in nutrition. Prob- 

 ably no other class of foods offers so attractive a field of study, in this 

 respect as fishery products, since it is commonly known that these 

 products contain minerals in quantity and variety, many of wliich 

 have been shown by scientific investigators to be of great importance 

 in both human and animal nutrition. During recent years the Bureau 

 has carried on an extensive study of the nutritive value of minerals in 

 fishery products. Toward this end, chemical analyses of the quantity 

 of these minerals in various fishery products of commercial importance 

 are being made. Following this, these fishery products are fed to lab- 

 oratory animals to determine the biological value of such minerals. 



The biochemical investigations during the past year have been of 

 two types; first, a study of those mineral elements contained in sea 

 foods which are considered to be of great importance in both human 

 and animal nutrition; and second, investigations of the characteristics 

 of those elements, also contained in sea foods, which are usually con- 

 sidered to be deleterious to health. Investigations of the iodine con- 

 tent of various fishery products of commercial im.portance by a more 

 recent method has revealed that the iodine content of some of them is 

 actually many times liigher than has previously been reported in this 

 country. For instance, the following average results are reported of 

 the iodine content, in parts per billion, of some of the important species 

 of fish, on a fresh basis: haddock, 5,130; cod, 1,030; and mullet, 4,850. 



The problem of the removal of arsenical spray residues from fruits 

 and vegetables in order to make those foods safe for human consump- 

 tion has recently focused the attention of investigators on the naturally 

 high arsenic content of sea foods. Because of increasing concern which 

 is being shown by scientific workers at the present time, an investiga- 

 tion was undertaken to study the characteristics of organic arsenic 

 as it is contained in marine products when fed to laboratory animals. 



The results of these investigations have revealed that there is a 

 difference in the metabolism of organic arsenic as it occurs in shrimp 

 as compared to inorganic arsenic and that while the inorganic arsenic 

 is absorbed and stored in the body, the organic arsenic from shrimp is 

 efiminated. Careful histological studies of the organs of the experi- 

 mental animals have failed to reveal any deleterious effects of this 

 element when fed in the form of shrimp. Like studies on the effect 

 of feeding organic copper in the form of "coppery green" oysters 

 have yielded similar results. 



Considering the results of the above-described work on arsenic and 

 copper, as well as the findings of other investigators that only a part 

 of the iron and copper of some foods is available for hemoglobin pro- 

 duction, it is becoming apparent that not only must the presenre of 

 an element in a food be proven, but its availability to the body must 

 be tested by animal experimentation methods. Consequently, it can 



