To possess her fully he must kill her’ (XI). When the deed is done, Jacques experiences an orgasmic sense of completion. ’An extraordinary feeling of elation bore him aloft. He savoured the long-awaited fulfilment of his desire’ (XI).

If, miraculously, at the age of twenty-six, Jacques has managed to avoid killing anyone it is mainly because he immerses himself in his job. Just as Flore eschews the company of men by escaping into the wild countryside near by, so Jacques avoids contact with women by spending every minute he can in the company of his locomotive. When he is not actually driving it, he attends to its needs, cleaning it and checking that it is in good working order. This exemplary commitment to his job is presented as a redirection and transference of Jacques’s sexual energies. The locomotive becomes his ‘mistress’. It is referred to not as ‘it’ but as ‘she’. Not only does Jacques love and care for her, he also learns how to ‘handle’ her, to master her and make her do his bidding. The locomotive is described as a creature with a mind of her own, who has to be properly looked after but whose whims must ultimately be subjugated to his will. It is no coincidence that Jacques’s murderous instinct resurfaces so dramatically on the day that the locomotive is taken away from him to be repaired and he is given an unexpected holiday from work. Zola seems to suggest that the only way of dealing with an inherited obsession is to construct an alternative obsession. At the point at which the novel begins, this tactic appears to have worked. But it has clearly not been easy. Although he cannot fully understand his affliction, Jacques has a keen sense of his own vulnerability; he knows that he is at risk day by day, hour by hour, minute by minute. When he is not performing his professional duties he must immure himself ‘like a monk’ (II) in his little attic room in the Rue Cardinet, at a safe distance from the teeming life of the city, a form of self-imposed sequestration and celibacy that complements the isolation provided by his job of work. It is against his will and better judgement that he is drawn from this life of voluntary exile.

The other murders in the novel have their part to play in this process, each of them impinging on Jacques’s consciousness in different ways. Standing alone beside the corpse of Grandmorin in the darkness and stillness of the night, Jacques longs to lift its head and contemplate the gaping wound in its throat. Moments before, he had come near to killing Flore and had had to flee from her, as previously he had fled from other potential victims. Now, in the presence of an achieved murder, his repeated failure to kill strikes him as an act of cowardice. He admires and envies the man who has had the courage to do this killing and vows that one day he will discover the courage to emulate him, a sinister declaration of intent to make himself worthy of what he appears at that moment to regard as a ‘calling’. Misard’s poisoning of his wife likewise acts upon Jacques as an enticement to kill. In this case what impresses him is the realization that murder can be achieved quietly and unobtrusively. It causes no great upheavals and goes unnoticed by both the police and the public at large. Misard kills his wife and goes about his job as if nothing had happened. The most powerful erosion of Jacques’s determination to resist the urge to kill, however, comes ironically from Séverine, who thereby paves the way for her own death. The knowledge that Séverine, seemingly so gentle and submissive, has participated in a murder inspires admiration in Jacques and a temporary suspension of the murderous impulse that contact with women normally inspires in him. Jacques’s admiration increases when he discovers that the motive behind the murder of Grandmorin was not merely theft, implying a bizarre, perverted scale of values which places other types of murder, including that to which he himself is drawn, into a more ‘worthy’ category. Jacques’s questioning of Séverine about the murder of Grandmorin is as intense in its different way as Roubaud’s brutal interrogation about her relationship with Grandmorin in the first chapter of the novel.