 Taking the example of herrings, if "prodigious numbers of them were not destroyed" each year they would soon cover the surface of the sea, but they would then be destroyed by "contagion and famine", so it was necessary and right that animals preyed on each other.Amidst debates on fears of British depopulation, Benjamin Franklin collected statistics of the American colonies which he published in his "Poor Richard Improved" of 1750 with the question of "how long will it be, before by an Increase of 64 "per Annum", 34,000 people will double themselves?