PREFACE. Vv 
the grakles in favor as locust-killers, that physicians 
were directed to proclaim that their flesh was un- 
wholesome, to prevent the people from eating grakle- 
pie, of which they were very fond. “ But this eztra- 
ordinary care,’ says Carpenter, “ was injurious. The 
birds soon again cleared the island of locusts, and de- 
stroyed the grubs which injure the coffee-plantations. 
But when this supply failed them, they proceeded to 
attack the corn-fields and orchards, and even killed 
the young of pigeons and other domestic birds. In 
order to restore the balance, a sort of Malthusian law 
was enacted to prevent their numbers exceeding the 
quantity of their legitimate food; and when thus kept 
in check, they continued to do good without any ad- 
mixture of evil.” 
Such facts as these indicate the wide benefits which 
the science of agriculture may derive from accurate 
observation of the habits and relations of animals. 
The more minds there are brought to engage in such 
observations, the more facts will be gathered into the 
common stock of information. And as the accuracy 
and extent of the observations depend on proper ed- 
ucation in the observer, it is important that the ob- 
serving powers be trained early; and we may say, 
therefore, that the whole subject of the relation of 
animal to vegetable life, so important to the farmer 
and the gardener, will never be thoroughly understood 
till the study of Nature be made prominent from the 
very beginning of education. 
As animals furnish man, to a great extent, with food 
and clothing, and a large variety of articles for use and 
ornament, an increased observation would undoubt- 
edly increase the amount of resources obtained from 
