ECONOMIC ZOOLOGY 407 



races of men, and even these have not been wholly re- 

 jected. 



The milk of the larger hoofed animals the cow, sheep, 

 goat, buffalo, and even the horse and the ass has formed 

 an important part in human diet. 



All the larger birds which are not strictly carnivorous 

 are eaten by man, and the eggs of these and many others, 

 domestic birds and wild birds, have formed a large part of 

 his diet. In China a certain species of swallow (Collocalia) 

 forms a nest in part from a secretion from its own stomach. 

 This substance forms an agreeable basis for soup, the so- 

 called edible bird's-nest. 



Among the reptiles certain species of turtles have flesh 

 of great delicacy for instance, certain land species, as 

 the Maryland diamond-back terrapin, and some of the 

 great sea-turtles. Among the amphibians, the chief food 

 product is found in the delicate muscles of the legs of 

 various species of frogs. 



Of the 12,000 known species of fishes, many are too 

 small to be worth taking. These serve as food for larger 

 fishes. A few dozen species in the tropics have flesh con- 

 taining a bitter alkaloid, which is more or less poisonous. 

 The great majority are, however, excellent as food, and up- 

 ward of 5,000 species may be fairly called food-fishes. Cer- 

 tain fishes yield jelly-like substances from the air-bladder 

 or other structures. The eggs of the sturgeon are prepared 

 to be eaten as " caviar." Among the fishes most delicious 

 as food, the eulachon of the Columbia Eiver perhaps ranks 

 first. The ayu, 01 samlet, of Japan resembles it. Next we 

 may place the pampano of the Gulf of Mexico, the Spanish 

 mackerel of the same region, the whitefish of the Great 

 Lakes, the bluefish and weakfish of New England, and the 

 various kinds of trout, grayling, bass, shad, and pickerel. 

 The sole, the surmullet, and the turbot rank among the 

 first of the fishes of Europe. Of far greater economic 

 value than any of these, from their exceeding abundance, 



