AV? U. S. BUREAU OF FISHERIES 
were then extracted and the oil was still in good condition, containing 
approximately 2,000 international units of vitamin A per gram. 
However, this oil was too low in vitamin D content to be considered 
as a commercial source of this vitamin. 
NUTRITIVE VALUE OF AQUATIC PRODUCTS 
This has always been an important phase of our technological inves- 
tigations because the relative nutritive value of the finished product 
is In most instances the true yardstick or measure of the value of a 
new method of processing or an improvement in existing methods in 
the industry For example, assuming that costs of production are 
equal in each case, if a new method of manufacturing fish meal, or a 
new method of freezing fish fillets, produces a finished product of 
better quality measured in terms of food value, then that is a true 
estimate of its worth or justification for its commercial application. 
MINERAL CONSTITUENTS OF FISHERY PRODUCTS 
In recent years, members of our technological staff have been mak- 
ing a detailed study of the mineral content of some of the more impor- 
tant commercial species of fish and shellfish. Although this work was 
interrupted by resignation of personnel, it is now completed and de- 
tailed data on the calcium, phosphorus, magnesium, iron, copper, and 
iodine content of the edible portion of various species of fish and shell- 
fish have been published in Investigational Report No. 41, entitled 
“The Mineral Content of the Edible Portions of Some American Fish- 
ery Products.”’ Fish fillets are about equal to the muscle cuts of beef 
in mineral content, except that the fish greatly exceeds the meat in 
iodine content. Canned salmon contains about 15 times as much cal- 
cium, almost twice'as much phosphorus, 20 times as much iodine, and 
approximately equal quantities of other minerals as beef round. Oys- 
ters, shrimp, and crab meat contain approximately half as much cal- 
cium, more than five times as much magnesium, and more phosphorus 
than an equal quantity of milk. In addition, these shellfish are a 
particularly good source of iron, copper, and iodine. 
CHEMICAL COMPOSITION AND NUTRITIVE VALUE OF FISH PROTEINS 
This study, begun several years ago, has now been completed. A 
report of the results of one phase of the project has been published in 
the scientific journal, Food Research, 1938, Volume 3, No. 5, under 
the title of ‘‘Nutritive Value for Growth of Some Proteins of Fishery 
Products.” By using an arbitrary factor of 100, the proteins of the 
following fish and shellfish fell into groups according to relative growth- 
promoting value, as compared to beef at a factor of 63: Oyster 100; 
pilchard, red snapper, shrimp and Boston mackerel 90; and shad, cod, 
croaker, and silver salmon 80. 
The chemical determinations of the principal amino acids in the 
proteins of several species of fish and shellfish have also been com- 
pleted and a report is now being prepared for publication. Arginine, 
histidine, and lysine were determined in the proteins of 20 species of 
fish and shellfish as follows: Cod, croaker, haddock, halibut, sea her- 
ring, lake trout, Boston mackerel, Spanish mackerel, mullet, pilchard, 
