THE OYSTER. II 



confined like land plants to the surface of the soil, and 

 while they are found in great abundance on the surface 

 of the mud, they are not restricted to it, for their food is 

 diffused in solution through the whole body of water, 

 and the mud itself is so light that it is in a state of 

 semi-suspension, and the little plants have ample 

 room among its particles. 



On land, the plant-producing area is a surface, but 

 the total plant-producing acreage of the bay is many 

 times greater than the superficial area of its bottom. 



As the little plants are bathed on all sides by food, 

 they do not have to go through the slow process of 

 sucking it up through roots and stems, and they grow 

 and multiply at a rate which has no parallel in ordinary 

 familiar plants ; and they would quickly choke up 

 the whole bay if they were not held in check ; but 

 their excessive increase is prevented by countless 

 minute animals which feast upon them and turn the 

 plant substance into animal matter, to become in their 

 turn food for larger animals. As a matter of fact, they 

 are not very abundant, but there is no difficulty in 

 finding them in any part of the bay, by straining the 

 water through a fine cloth. In this way we obtain a 

 fine sediment, which is shown by the microscope to 

 consist almost entirely of them. 



The variety of these microscopic plants and animals 

 is very great, and a series of big volumes would be 

 needed to describe the microscopic flora and fauna of 

 the bay. Most of them occur in other waters as well, 

 but many are peculiar to the bay, which is an excep- 

 tionally favored spot for their growth. 



The exploration of this invisible world with a 



