Although of extraordinary erudition his learning did not, as too often happens, obscure the powers of original thought and reason. Bayle, writing at the end of the seventeenth century, has characterised him as “the greatest philosopher amongst scholars, and the greatest scholar amongst philosophers;” and Newton conceived the same high esteem for the great vindicator of Epikurus.[120] It is in his celebrated letter to his friend Van Helmont, that Gassendi deals with the irrational assertions of certain physiologists, apparently more devoted to the defence of the orthodox diet than to the discovery of unwelcome truth, as to the character of the human teeth:-- “I was contending,” he writes to his medical friend, “that from the conformation of our teeth we do not appear to be adapted by Nature to the use of a flesh diet, since all animals (I spoke of terrestrials) which Nature has formed to feed on flesh have their teeth long, conical, sharp, uneven, and with intervals between them--of which kind are lions, tigers, wolves, dogs, cats, and others. But those who are made to subsist only on herbs and fruits have their teeth short, broad, blunt, close to one another, and distributed in even rows. Of this sort are horses, cows, deer, sheep, goats, and some others. And further--that men have received from Nature teeth which are unlike those of the first class, and resemble those of the second. It is therefore probable, since men are land animals, that Nature intended them to follow, in the selection of their food, not the carnivorous tribes, but those races of animals which are contented with the simple productions of the earth.... Wherefore, I here repeat that from the primæval institution of our nature, the teeth were destined to the mastication, not of flesh, but of fruits. As for flesh, true, indeed, it is that man is sustained on flesh. But _how many things_, let me ask, _does man do every day which are contrary to, or beside, his nature_? So great, and so general, is the perversion of his mode of life, which has, as it were, eaten into his flesh by a sort of deadly contagion (_contagione veluti quâdam jam inusta est_), that he appears to have put on another disposition. Hence, the whole care and concern of philosophy and moral instruction ought to consist in leading men back to the paths of Nature.”