Zola's particular mentality explains both his life and his work. He systematised in literature the realistic tendencies of the philosophy of Comte and Taine; and he carried that systematisation to its farthest limit by creating the novel of complete observation (_le roman d'observation intégrale_), in which he studied heredity under all its aspects, recoiling from no audacity either of observation or of expression. By mere reasoning, adds Dr. Toulouse, whom we still follow,[6] Zola's systematic mind traced for itself a course of action which was often at variance with his instincts, yet he followed it perseveringly, sustained merely by his conception of duty. His tendency to gout and corpulence (which last he overcame by sheer determination) must have predisposed him to laziness, but he mastered any such inclination by compelling himself to do a certain amount of work every day. As a rule he then wrote quite sufficient "copy" to form three pages of one of his books, in addition to occasional newspaper articles. He also carried on an extensive correspondence, yet the only time when he had recourse to secretarial help was the period of the Dreyfus case. _Nulla dies sine linea_ was a motto he had adopted early in life, and lest it should be forgotten it was graven in letters of gold over the fireplace of his large study at Médan, where most of his books were written. At Médan he rose at eight o'clock, went for an hour's stroll, seating himself at his writing table at nine and writing till one o'clock, usually on an empty stomach, for after he had resolved to conquer his corpulence his first meal consisted generally of a mere crust of bread, though now and again he might partake of a couple of eggs "on the plate," which to please him had to be cooked to a nicety. At one o'clock he lunched; and then, perhaps, came a short nap, after which he either read the papers or worked at an article or went out walking, cycling, or boating. If he were at home in the afternoon, he drank a cup of tea, and this carried him on till dinner, which was served at half-past seven. Afterwards, if friends were staying with him, there might be a game of billiards or a quiet chat over another cup of tea. For some years he drank nothing at all with his meals, at which he preferred his fish fried and his meat grilled; but later he allowed himself a glass of water, and on a hot afternoon, if he were thirsty, he now and then indulged in a little white wine and eau de Seltz. Red wine he did not touch from 1887 till the time of his death; but occasionally, after a meal or in the evening, he treated himself to a thimbleful of old cognac or some liqueur. This happened perhaps once a week, not more frequently, so it will be seen that he was almost a total abstainer.