"What a help that must be to your parents and to the world at large!"
said the frog with sarcasm. "I am surprised that we never see the
results of such hard labour. Do you know how useful even our smallest
tadpoles are? Without them this pond would be no longer beautiful, but
foul and ill-smelling. As for what we do when we are grown up, modesty
forbids me to praise the frogs, but you know what a toad is worth to
mankind?"

"No," said Bobby. "About two cents, I guess." Bobby didn't intend to be
rude. He thought this a liberal valuation.

"Twenty dollars a year, as estimated by the Department of Agriculture!"
cried the frog triumphantly. "What do you think of that?"

"I should like to know why," said Bobby, looking as if he thought
Professor Rana was making fun of him.

"What are the greatest enemies of mankind?" asked the professor, peering
over his goggles at poor Bobby.

"Tigers," said Bobby, promptly; "or wolves."

"Wrong," said the lecturer. "Insects. Insects destroy property on this
continent to the amount of over four hundred million dollars annually.
Insects destroy the crops upon which man depends for his food. Going to
school hasn't made you very wise, has it? Well, the toads are insect
destroyers. That's their business. If the State only knew enough to make
use of them, millions of dollars might be saved every year. Does it seem
to you that the human animal is so clever as it might be, when it allows