NUTRITIVE VALUE OF FISH ANI> SHELLFISH 513 



portion of the water existing in the flesh of the fish is removed by 

 salting and drying operations, salt fish like cod and smoked herring 

 are quite highly concentrated forms of protein. In the case of smoked 

 herring there is the additional advantage of a rather high percentage 

 of fat. Similarly, salt mackerel owes its chief fuel value to its very 

 high content of oil; namely, 25.1 per cent. This, together with its 

 protein content, gives it the unusually high fuel value of 1,405 calories 

 ■per pound. However, probably the most commonly used form of 

 salted fish is the salt cod. This does not gain much in food value 

 from its fat content, which is very low, but does have a considerable 

 percentage of protein— namely, 26.3 per cent — and a total fuel value 

 of 502 calories per pound. Pickled herring and mild-cured salmon 

 are prepared in large quantities and used in many countries. 



MOLLUSKS, CRUSTACEANS, ETC. 



Up to the present point we have been considering only fish in the 

 narrow meanmg of the word. However, it was probably quite early 

 in the development of mankind that they learned to utilize oysters 

 and clams as well as crabs, slu-imp, etc., which they could gather 

 along the seashore. Just as pointed out in the case of the early 

 native tribes flocking to the rivers at certain seasons in order to 

 catch fish and preserve them for the winter, it is also true that in 

 Europe and North America the natives frequented certain favorite 

 places along the shores in order to enjoy oysters and clams. Judging 

 by the enormous size of some sheU mounds in Europe and on both 

 our coasts, large quantities of these moUusks must have been con- 

 sumed over long periods of time. The fragments of pottery, arrow- 

 heads, and other prehistoric traces show that these mounds were 

 built up slowly, sometimes one over another, where the remains of 

 one civilization would be buried along with the shells, only to be 

 followed by later deposits. Modern man has not lost his taste for 

 moUusks and crustaceans, and the consumption of oysters, clams, 

 scallops, mussels, lobsters, crabs, and shrimp is quite large. 



The most important of the moUusks, industrially, is the oyster. 

 Great quantities are eaten raw on the seaboard and also shipped 

 long distances inland in refrigerator cars. The flavor of the oyster 

 seems to be one that is particularly attractive to many people. From 

 the standpoint of composition the oyster is very interesting for the 

 reason that a quart of oysters and a quart of milk have very nearly 

 the same composition and about the same food value. Oysters 

 are also pecuHar from a scientific standpoint in that they contain 

 some imusual inorganic constituents like copper and zinc. Of 

 course, not enough of these metals is present to affect injuriously 

 their value for human food. 



Generally speaking the food value of the edible part of moUusks 

 and crustaceans is not as high as in fish flesh. This is made plain 

 in Table 8. The reason for this is that moUusks do not contain 

 very much fat, whUe the flesh of many fishes does. On the other 

 hand, there is one characteristic of this class of sea foods which is 

 interesting and important; that is, they contain some carbohydrate 

 or starchy type of nutrients, which is quite unusual in sea foods. 

 As a matter of fact, carbohydrates are not determined in ordinary 

 analyses of fish flesh because they exist in quantities of considerably 



