Silver has been discovered in all the states, either alone or in the form of sulphides, antimonial and arsenical ores, chloride, bromide,.
To check them, " grease-banding " round the trees has been adopted; but as many other pests eat the leafage, it is best to kill all at once by spraying with arsenical poisons.
For insects provided with a biting mouth, which take nourishment from the whole leaf, shoot or fruit, the poisonous washes used are chiefly arsenical.
The two most useful arsenical sprays are Paris green and arsenate of lead.
Arsenical soap is very much employed by taxidermists for the preservation of the skins of birds and mammals.