In 1749 appeared his Histoire Naturelle des Oiseaux, in eight volumes and six supplements—a beautiful illustrated work, in which is painted in glowing colours the manners and habits of birds. In particular and minute observation he excelled, and by his indefatigable researches he made most valuable additions to science.
Buffon rejected the principles of classifications in use in his day, and threw his subjects into groups. He was not free from bias, and his prepossession for a favourite doctrine led him astray. He rejected the works on classification of Ray, Tournefort, Bernard de Jussieu, and Linnæus; but in his Histoire Naturelle des Oiseaux he felt more and more the necessity of arranging birds according to their affinities.
In 1774 Buffon published his Histoire des Minéraux—a work of great importance and value.
The same year that Voltaire and Rousseau died, Buffon ended his labours, and joined the majority on 16th April 1778. His last words to his son were: "Never quit the path of honour and of virtue; it is the only way to be happy." He was buried with public honours in the Cimetière du Père la Chaise.
He died one year before the advent of the French Revolution, and his only son was guillotined fifteen days before the fall of Robespierre. During the Reign of Terror the remains of the great zoologist were torn from the tomb, and the monument which was erected to
