(18.) We find it stated, that there are some men whose bones are solid, and devoid of marrow,[1055] and that one mark of such persons is the fact that they are never thirsty, and emit no perspiration. At the same time, we know that by the exercise of a resolute determination, any one may resist the feeling of thirst; a fact which was especially exemplified in the case of Julius Viator, a Roman of equestrian rank, but by birth one of the Vocontii, a nation on terms of alliance with us. Having, in his youth, been attacked by dropsy, and forbidden the use of liquids by his physicians,[1056] use with him became a second nature, and so, in his old age, he never took any drink at all. Other persons also, have, by the exercise of a strong determination, laid similar restraints upon themselves. (19.) It is said that Crassus, the grandfather of Crassus, who was slain by the Parthians, was never known to laugh; from which circumstance he obtained the name of Agelastus.[1057] There are other persons again, who have never been seen to weep. Socrates, who was so famous for his wisdom, always appeared with the same countenance, and was never known to appear either more gay or more sad than ordinary. This even tenor of the mind, however, sometimes degenerates into a sort of harshness, and a rigorous and inflexible sternness of nature, entirely effacing all the human affections. The Greeks, among whom there have been many persons of this description, are in the habit of calling them Ἀπαθεῖς.[1058] A very remarkable thing, too, is the fact, that among these persons are to be found some of the greatest masters of philosophy. Diogenes the Cynic, for instance, Pyrrho, Heraclitus, and Timon, which last allowed himself to be so entirely carried away by this spirit, as to become a hater of all mankind. Less important peculiarities of nature, again, are to be observed in many persons; Antonia,[1059] for instance, the wife of Drusus, was never known to expectorate; and Pomponius, the poet, a man of consular rank, was never troubled with eructation. Those rare instances of men,[1060] whose bones are naturally solid and without marrow, are known to us as men “of horn.”[1061] CHAP. 19. (20.)—INSTANCES OF EXTRAORDINARY STRENGTH.