t how could green leaves, sap, flowers and pollen, be furnished to those insects absolutely requiring them for existence? Thirty species of insects feed on the nettle, but not one of them could live on dried nettles. Rösel calculates that two hundred species subsist on the oak; but the oak must be in a growing condition to supply them with food. In no other way, then, could the insects have been preserved alive than by large green-houses, the heat so applied as to suit the plants of both temperate and tropical climates, and the insects so distributed among them, that each could obtain its appropriate nourishment.
Fruit would be necessary for the four hundred and forty-two monkeys, for the plantain-eaters, the fruit-pigeons of the Spice Islands that feed on nutmegs, for the toucans and the flocks of parrots, parroquets, cockatoos, and other fruit-eating birds. As they did not know how to can fruit in those days, and dried fruit would be altogether unsuitable, there must have been a large green-hous