Cuvier, like Sir Isaac Newton, was born with such a feeble and sickly constitution, that he was scarcely expected to reach the years of manhood. His affectionate mother watched over his varying health, instilled into his mind the first lessons of religion, and had taught him to read fluently before he had completed his fourth year. She made him repeat to her his Latin lessons, though ignorant herself of the language; she conducted him every morning to school; made him practise drawing under her own superintendence, and supplied him with the best works on history and literature. His father had destined him for the army. In the library of the Gymnasium, where he stood at the head of the classes of history, geography, and mathematics, he lighted upon a copy of Gesner's History of Animals and Serpents, with coloured plates; and, about the same time, he had discovered a complete copy of Buffon among the books of one of his relatives. His taste for Natural History now became a passion. He copied the figures which these works contained, and coloured them in conformity with the descriptions; whilst he did not overlook the intellectual beauties of his author.

In the fourteenth year of his age he was appointed president of a society of his schoolfellows, which he was the means of organising, and of which he drew up the rules; and seated on the foot of his bed, which was the president's chair, he first showed his oratorical powers in the discussion of various questions, suggested by the reading of books of natural history and travels, which was the principal object of the society.

When at the age of nineteen, the casual dissection of a colmar, a species of cuttle-fish, induced Cuvier to study the anatomy of the mollusca; and the examination of some fossil terebratulÆ, which had been dug up near FÉcamp, in June, 1791, suggested to him the idea of comparing fossil with living animals; and thus, as he himself said, "the germ of his two most important labours—the comparison of fossil with living species, and the reform of the classification of the animal kingdom—had their origin at this epoch."