6 THE OYSTER. 



ocean is of such a character that its existence is known 

 only to naturalists. 



If there were no plants all animals would starve, and 

 no animal is a direct food-producer, for it can furnish 

 nothing except what it has got from plants. 



Now, for the purposes of animal life a small plant is 

 as effective as a large one, for however small it may 

 be, it still has the power, which is possessed by no 

 animal, to gather up the inorganic matter of the earth, 

 and to turn it into vegetable matter fit for the nourish- 

 ment of animals. Microscopic plants can do this work 

 as well as great forests of lofty trees, provided they 

 are numerous enough, and size counts for nothing. 



Every one knows that the sea is rich in animal life ; 

 that it contains great banks covered with cod and had- 

 dock, miles and miles of water crowded full of mack- 

 erel and herring, and great monsters of the deep such 

 as the whales and sharks. To the superficial observer 

 the vegetation of the sea appears to be very scanty, 

 and, except for the fringe of sea-weeds along the shore, 

 the great ocean seems, so far as plant life is concerned, 

 to be a barren desert. If it be true that all animals 

 depend on plants for their food, the vegetation of the 

 ocean seems totally inadequate for the support of its , 

 animal life. 



The microscope shows that its surface swarms with 

 minute plants, most of them of strange forms, totally 

 unlike any which are familiar, and having nothing in 

 common with the well known trees and herbs and 

 grasses of the land except the power to change inor- 

 ganic matter into food which is fit for animals. 



Most of these plants are so small that they are abso- 



