372 READINGS IN BIOLOGICAL SCIENCE 



foxes, but fisher, marten, mink, skunk and other animals have been culti- 

 vated for their furs. 



The "king" salmon occurs on both coasts of the pacific from California 

 and China north to Bering Straits. During the winter the fish sojourn in 

 the sea, but in early spring they slowly gather in the rivers and begin the 

 long and arduous journey to their breeding grounds, which in the Yukon 

 may be over 2,000 miles from the sea. In the ascent of the rivers they per- 

 form prodigious feats, ascending falls 10-15 ^^^^ ^^ height. Arrived on the 

 spawning grounds in autumn the male excavates a little hollow in the gravel 

 of the stream bed, where the female deposits her eggs, upon which the 

 male sheds the "milt" or sperms, after which they cover them with gravel; 

 and then the function of reproduction performed, which is the crowning 

 act in the life of animal or plant, they float downstream to die. 



The average number of eggs laid by a female is four thousand. If one- 

 half of these developed into females and reached maturity in four years, 

 and if their progeny in turn were all to reach maturity, one-half being 

 females, this rate of increase remaining constant from generation to genera- 

 tion, there would result in 32 years 256,000,000,000,000,000,000,000,000 

 salmon weighing 2,816,000,000,000,000,000,000,000 tons or 468 times the 

 mass of the earth. (Such an increase does not occur of course because of 

 the many natural enemies of the salmon including man.) 



Sealing privileges have long been a bone of bitter contention between 

 American, Russians, Canadians, and more recently the Japanese. The 

 Pribilof Islands, the principal sealing grounds, originally belonged to Russia. 

 With the sale of Alaska to the United States in 1867 these rights passed to 

 our government. It is an interesting commentary on the foresight of the 

 opponents of the Alaska purchase proposition, that from 1 870-1 890 our 

 government received in leases, royalties, and duties on furs made up in 

 London, but most of which came originally from Alaska, some |i 3,000,000, 

 or nearly double the price paid for the entire territory. 



>>><<<■ 



WONDER PLANTS OF COMMERCE AND INDUSTRY ^ 

 A . HYATT VERRILL 



One of the most wonderful features of plants is the important part they 

 play in our commerce and industries, as well as in our daily lives. 



This article, for example, would not be possible were it not for plants. 

 Even if the paper upon which it is printed had been made from old rags 

 it would still be a plant product, for the rags used would have been cotton 

 or linen cloth made from plant fibers. The same plants have supplied the 



* From Wonder Plants and Plant Wonders by A. Hyatt Verrill, D. Appleton- 

 Century Co. Copyright 1939. 



