Elizabeth was the one who had the last word, and I find it very easy to imagine a friendship developing between Elizabeth and Julia. I haven't specifically looked for that friendship when I've been watching, but they had a lot in common. They were both intelligent women with experience running a business in a world in which the businesses were usually run by men, and I think each of them had spent much of their adult lives with very few - if any - women friends. I suppose the sedatives were convenient, but Elizabeth had some little pink pills or some such thing before Julia come along - I think I remember remarking on them in a Watching Project post once. So I think the deciding factor for Elizabeth was that she just liked having Julia around. But I haven't any specific scenes to back that up.