But circumstances and place made very little difference to the young naturalist, and Normandy furnished him with the same material for study that Würtemberg had offered. The world of nature was still around him, and the sound of the waves dashing against the coast became as great an inspiration as had been the groves and fields around Stuttgart. He at once turned his attention to the study of marine animals, and ha the necessary books been at hand his pursuit of this branch of natural history would soon have yielded the most satisfactory results; but away from libraries, and with no one to give him needed information, he was obliged to leave this study incomplete.

He consoled himself somewhat by making drawings of a magnificent collection of Mediterranean fishes owned by a gentleman of Caen, and although he was debarred from entering into an exhaustive study of fishes, and the absence of books proved a serious obstacle, yet it was while he was a tutor at Caen that Cuvier entered upon that particular branch of study that was destined to make him famous. Up to the latter part of the seventeenth century the attention of naturalists had been directed more particularly toward the study of plants, as these could be more easily procured, preserved with less expense, and needed smaller space for collections than any other object. Thus it happened that botany had profited more than any other branch of natural history by the works of illustrious naturalists, and was, comparatively speaking, far in advance of the others.

Linnæus and other investigators had studied animals with much painstaking interest, but their conclusions were far from being satisfactory, and later naturalists found great difficulty in reconciling new specimens with their assigned places in the accepted systems.

Linnæus and his followers divided the animal kingdom into six classes, founded principally upon the breathing and blood, the entire zoölogical arrangement resting upon observation alone.

But this method had so much in it that was objectionable, that from time to time new systems were dreamed of and naturalists were continually trying to solve the difficulty. But it was reserved for Cuvier to advance a new theory so startling, and yet so conclusive, that in a few years it commanded the admiration of the civilized world.

Examining one day some fossils that had been dug up near Fécamp, the thought came to him of comparing fossil with recent species, and this little circumstance led eventually to the establishment of that great system which was to superseded all others.

Filled with his new idea Cuvier at once proceeded to make the anatomical studies of the mollusks, and careful comparisons proved to him that a system based upon the internal structure of animals would solve all the difficulties that had hitherto been considered insurmountable.

The results of his investigations were carefully written out, and although he apologized for his work by saying that it doubtless contained nothing that was not known to the naturalists of Paris who had the benefit of books and collections that were denied him, yet is was soon found that the manuscripts were full of new facts, and suggestions superior to any that had yet appeared.

It was the custom of Cuvier at this time to attend the meetings of a little society that had for its object the discussion of agricultural topics, and here he met M. Tessier, who had sought in Normandy safety from the horrors of the French Revolution. M. Tessier was an author on agricultural subjects, and displayed so much knowledge in his arguments that Cuvier recognized him, although he was living under an assumed name, and was supposed to be a surgeon in a regiment quartered near Caen. The fugitive was preparing to give himself up for lost upon his recognition; but Cuvier assured him that he would, on the contrary, only be the object of the greatest solicitude, and thus a friendship was begun which brought the most lasting benefits to the young tutor.

M. Tessier was astonished at this learning, and familiarity with comparative anatomy, and it was through his influence that Cuvier first became known to the savants of France. He wrote to his friends that Cuvier was "a violet hid in the grass," and that nothing could redound more to their credit than to draw him from his retreat and give the world the benefit of his unusual talents. In consequence of this interested Cuvier's merits were at once recognized by some of the most learned men in Europe; his articles on the mollusks were published in the leading scientific journals, and he speedily became known as on of whom great things might be expected. His new friends did not allow their interest to flag, and in 1795 he was called to Paris and given a professorship.

He now devoted himself more eagerly than ever to his scientific pursuits, and carried the study of comparative anatomy far beyond any point that it had before reached, his work in this department never ceasing through his entire life.

Many other branches of knowledge commanded his attention and were enriched by his toil, but everything was made subservient to the great principle which he hoped to establish by means of comparative anatomy. Fossils were brought to him from all parts of the world, and he gave his days and nights to the task of comparing them with the bones of recent animals, and giving them their place in the series of beings.

His general plan was to take the best known living species, examine their bones, describe the countries they inhabit and the number of kinds, and then compare them with the bones found in the fossil state.

Many interesting discoveries were made in this connection, and Cuvier's investigations destroyed many of the illusions that had always hung around the subject. From the most ancient times there had been a popular belief in the finding of the tombs of giants, and in many places there were kept collections of enormous bones that were said to belong to the human species; and even in the time of Cuvier this belief, strengthened by the ever-present love of the marvelous, still held sway over people's minds and often gave rise to the most absurd stories. Giants' bones were continually being discovered in all places, and many cities counted them among their most interesting treasures. In Switzerland they claimed to have found relics of enormous giants that lived before the deluge, and in France, a sepulcher thirty feet long was discovered in scribed with the name of one of the kings of the Cimbri. The city of Lucerne had stamped on its coat-of-arms the figures of some giants, nineteen feet long, that had been accidentally found, and exaggerated accounts of the discovery of similar bones elsewhere were received with the most credulous wonder.

But Cuvier visited England, Holland, Germany, Italy, and other places where the human fossils had been found, and proved beyond the shadow of a doubt that the bones belonged to the elephants that had wandered over those countries in the pre-historic ages. And although the wonder-lovers were loath to give up their giants, there were obliged to accept such strong proof as Cuvier offered, and turn their attention to something else. Then came marvelous stories of the monster beasts of the New World, which was as yet almost an unknown country to naturalists, and its vast plains and immense forest were speedily peopled with gigantic quadrupeds frightful in appearance and combining the worst features of the elephant and rhinoceros.

But again Cuvier came forward and demonstrated that the fossil remains of the American mammoth and mastodon proved conclusively that the conditions for their existence no longer remained, and that their presence would be as foreign to the new world as that of the hippopotamus or zebra. Many only listened curiously to the se revelations, but the scientific world was delighted, and accepted with the words of the man who could thus recreate the ancient world and bring before their minds its mighty forests and endless plains, and bottomless marshes, with its gigantic inhabitants roving in peaceful bands, or fighting their fierce battles, unseen by human eye, and yet leaving such unimpeachable records behind that those long distant ages seemed almost as near as the days of some by-gone summer.

And to one ignorant of such subjects the conclusions reached could only seem marvelous, for how stupendous seemed that knowledge of the laws of organization which could reconstruct an entire animal from the fragments of bones scattered through the layers of the earth, and assign to it its place in history; reproduction again its long-vanished home, and describing it habits and even its tastes, till the dim past was filled with a long procession of living figures, each distinct and interesting, and connected by indissoluble links with the present, from the might mammoth that tramped awkwardly through the wilderness, and the great winged birds that brooded in gigantic palms, or circled over somber northern plains, to the fleet-footed quadrupeds that now dart in and out through the sunlit paths of the forest, or the robins that sing in the white blossoms of the cherry-trees in the springtime.

The publication of the work on fossils at once led to world-wide fame, and it was immediately seen that Cuvier held the key to the mystery that had puzzled so many. For although it had previously been tried to make use of fossils in the study of geology, yet to Cuvier alone belongs the credit of developing the idea to an extent undreamed of by the originators, and of applying the same principle to the study of animals, and by combing zoölogy and anatomy found a system of classification that would rest upon incontrovertible principles.

He abandoned the Linnæan system, and divided the animal kingdom into four classes—vertebrates, or back-boned animals, articulates, or jointed animals, mollusks, or soft bodied animals, and radiates, or star-shaped animals—claiming that there existed in nature only four principal forms or general plans, according to which all animals were moulded. This whole animal kingdom was reviewed in support for this theory, his anatomical studies embracing every variety of species known, and the results were embodied in his great works on "Fossil Remains" and on the "Distribution of the Animal Kingdom."

His conclusions showed such minute investigation, careful research, and wide knowledge, that there could be no hesitation about the acceptance of his theory by the scientific world, and in a short time it had gained such favor as to supersede all others. The materials for the founding of the new system naturally included a wide range of study, and Cuvier was the author of innumerable volumes embracing works on natural history.

He was, besides, appointed to various positions of honor in the Government from time to time, and was charged with many offices relating to educational matters, and held important places of trust during the unsettled years that followed the days of '93.

His early manhood was passed during the terrible struggle of the First Revolution; he lived under Louis XVI., the Directory, Napoleon, Louis XVIII., the Second Revolution, Charles X., and was made a peer of France by Louis Philippe, but through all these changes he kept the great purpose of his life steadily in view, and never wavered in his determination to place zoölogy upon a firmer foundation than he had found it.

That his efforts were deservedly crowned with success was the greatest satisfaction of his life, and he felt amply rewarded for all his unwearied toil by the assurance that he had brought to the world a gift by means of which science was brought to the threshold of a new epoch, more brilliant than any it had yet seen.