That's right, I was forgetting serialized novels. They were big, too.
That method of Dumas was how Dostoevsky worked, at least some of the time--not knowing exactly what he was doing in a novel until after its first chapters had already appeared in a magazine. Presumably his gambling debts had something to do with this habit of working, although he supposedly had a case of what they call "hypergraphia," and could produce an incredibly amount of writing in a short amount of time.
