It is most probable that these insects had been imported from some vessel, as they attacked two opposite ends of the same town, the centre being untouched. M. de Quatrefages tried many experiments on these insects with a view of discovering some method of destroying them, and came to the conclusion that if _chlorine_ could be injected in sufficient quantities, it would in time have the desired result. The termite or white ant is represented by Linnæus as the greatest pest of both Indies, because of the havoc they make in all buildings of wood, in utensils, and in furniture. They frequently construct nests within the roofs and other parts of houses, which they destroy if not speedily extirpated. The larger species enter under the foundations of houses, making their way through the floors and up the posts of buildings, destroying all before them; and so little is seen of their operations that a well-painted building is sometimes found to be a mere shell, so thin that the woodwork may be punched through with the point of the finger. Many kinds of wood _in Brazil_[25] are impervious to the termite, which insect generally selects the more porous woods, and especially if these are in contact with the earth. In dry places, and with _a free circulation of air_, it does not prefer timber thus situated; and it is found that roofs of buildings of _good_ and well-seasoned native wood resist for an indefinite period both the climate and the termite. As a general rule, Brazilian timber is very brittle. It shows the difference of effects between one climate and another, that in Brazil the more porous and open-grained timbers are most subject to the attacks of the white ant, especially if they are in contact with the earth; but _in Australia_ it is the reverse, for there it is the hardest description of timber that those insects first attack. There is one wood in particular, in common use, to which this remark applies, namely, “Iron Bark.” Its density is so great that it sinks in water, and its strength is extraordinary, and yet the wood the white ants are particularly fond of. In the West Indies, the ants prefer hard woods. _At Bahia_, the timber is less affected by the termite than _in Pernambuco_; but even in the latter place the white ant does not like dry places with a free circulation of air.