INSECTIVOROUS ANIMALS 283 



a tadpole. If they tend to eat the aquarium bare, add 

 fresh supplies of slime and plants from the pond and, in 

 a word, keep them healthy, vigorous, and growing. 



Encourage as many children as possible to provide little 

 pools in their gardens, stock them well with water lilies, 

 pickerel weed, cat-tails, iris, and other of our interesting 

 aquatic plants, and put in as many toads' eggs or tadpoles 

 as the pool will support. For this purpose a water-tight 

 box or tub may be set in the ground, or a more natural 

 pool may be made by arranging large flat stones around a 

 hole in the ground and plastering up the cracks between 

 them with water-lime cement. The top of any such recep- 

 tacle should be two or three inches below the surface, and 

 the earth well packed around the edges to prevent rains 

 from splashing out its occupants. If natural food be not 

 abundant, its place may be supplied by bits of dog biscuit, 

 fresh meat, fish, or even bread, but care should be taken 

 to put in no more than is eaten clean or to remove 

 uneaten pieces before they foul the water. In this way, 

 without appreciable expense, any child can raise toads by 

 thousands, until many of our most injurious insect pests 

 become curiosities. The danger of ever getting too many 

 toads we will discuss in a moment. 



Emphasize throughout these lessons the work the tad- 

 poles are doing in the water. They are known as the 

 " best scavengers " of aquaria, and it is difficult to keep an 

 aquarium clean without them. Their little horny jaws 

 are continually scraping the slimy growths from every- 

 thing in the water. Their food at this time is commonly 

 stated to be vegetable, but if one examines these slimes 

 with a microscope, he will always find a considerable 



