168 THE GARDEN OF EARTH 



from some other plant upon which they live. Parasites 

 of various kinds are common in the Vegetable World, 

 and they are usually looked upon as hurtful, as bringing 

 disease, if not death, to the tree or herb attacked. 



The smallest and most abundant of these unwelcome 

 guests are the Bacteria — tiny invisible hordes ! We 

 spoke of them as among the very lowest on the rungs of a 

 ladder of vegetable growths. It is not certain that all 

 the Bacteria are " vegetable " in nature, for some may 

 be " animal," but at least very many of them are. And 

 their numbers are simply enormous, far beyond our 

 power to reckon. 



Not much has been said, so far, about the quantities of 

 Seeds, which can be produced by a flowering plant in one 

 season. These quantities differ immensely, for some 

 plants bring forth very few, perhaps one or two seeds 

 only to a single bloom. But they are rather rare, and 

 with others matters are widely the reverse. 



For instance, a single plant has been known to grow 

 ten thousand seeds in a year ; another sixty thousand ; 

 another a hundred thousand; another seven hundred 

 thousand ; and so on. 



And if each of those thousands of seeds should produce 

 next year another ten or a hundred thousand, and each 

 of those again the same amounts in the year after — ^think 

 what it would all come to. Naturally, they do not, 

 because many seeds must always fail, from want of 

 water or of room to grow or some other cause. 



So much for the manufacture of seeds by flowering 

 plants. But when we go down the ladder to the swarm- 

 ing Bacteria, these numbers are far surpassed. Here we 



