2 MICROSCOPIC PLANTS. [CHAP. 



means of obtaining these low forms of vegetation is 

 to collect a quantity of Duckweed, "the green mantle 

 of the standing pool," from the surface of a stagnant 

 pond, together with some of the water. If a single 

 plant of Duckweed be put on a glass slip and covered 

 with the thin glass used for the purpose, then placed 

 under the microscope, a number of distinct forms will 

 be seen some vegetable, some animal. With the 

 latter we have nothing to do in the present volume ; 

 we shall simply ignore them. 



Most of the minute plants found in ponds belong 

 to the same tribe as the Seaweeds (the Algcs], but 

 we shall also have something to say of the tiny re- 

 presentatives of the Mushroom family (the Fungi), 

 low forms of which abound on all decaying sub- 

 stances. 



One of the simplest of the Algae and one of the 

 most plentiful is the Protococcus. Our readers will 

 probably be struck with the fact that these very 

 small plants have very large names. We hope they 

 will not be frightened, for, after all, it is a small 

 matter ; and when they are learnt, they give us some 

 fact about the owner, such as it would take many 

 words in English to make clear. In this instance it 

 means literally first berry or plant, that is, the simplest 

 form of plant. It is found in abundance in ponds, 

 ditches, rain-water butts, and in fact wherever water 

 accumulates in little pools. It consists of a single 

 cell or sac containing a jelly-like substance called 

 protoplasm. It is this protoplasm which constitutes 

 the living part of the plant ; the covering (cell) can- 

 not grow, it requires to be added to by the proto- 



