Such were the conditions under which, and the methods by which, Pliny compiled his encyclopedia on nature. No single writer either Greek or Latin, he tells us, had ever before attempted so extensive a task. He adds that he treats of some twenty thousand topics gleaned from the perusal of about two thousand volumes by one hundred authors.[123] Judging from his bibliographies and citations, however, he would seem to have utilized more than one hundred authors. But possibly he had not read all the writers mentioned in his bibliographies. He affirms that previous students have had access to but few of the volumes which he has used, and that he adds many things unknown to his ancient authorities and recently discovered. Occasionally he shows an acquaintance with beliefs and practices of the Gauls and Druids. Thus his work assumes to be something more than a compilation from other books. He says, however, that no doubt he has omitted much, since he is only human and has had many other demands upon his time. He admits that his subject is dry (_sterilis materia_) and does not lend itself to literary exhibitions, nor include matters stimulating to write about and pleasant to read about, like speeches and marvelous occurrences and varied incidents. Nor does it permit purity and elegance of diction, since one must at times employ the terminology of rustics, foreigners, and even barbarians. Furthermore, “it is an arduous task to give novelty to what is ancient, authority to what is new, interest to what is obsolete, light to what is obscure, charm to what is loathsome”—as many of his medicinal simples undoubtedly are—“credit to what is dubious.” [Sidenote: His devotion to science.] It is a great comfort to Pliny, however, in his immense task, when many laugh at him as wasting his time over worthless trifles, to reflect that he is being spurned along with Nature.[124] In another passage[125] he contrasts the blood and slaughter of military history with the benefits bestowed upon mankind by astronomers. In a third passage[126] he looks back regretfully at the widespread interest in science among the Greeks, although those were times of political disunion and strife and although communication between different lands was interrupted by piracy as well as war, whereas now, with the whole empire at peace, not only is no new scientific inquiry undertaken, but men do not even thoroughly study the works of the ancients, and are intent on the acquisition of lucre rather than learning. These and other passages which might be cited attest Pliny’s devotion to science. [Sidenote: Conflict of science and religion.]