lest, conj.

1. a. Used as a negative particle of intention or purpose, introducing a clause expressive of something to be prevented or guarded against; = Latin nē, English that..not, for fear that.

....

2. Used after verbs of fearing, or phrases indicating apprehension or danger, to introduce a clause expressing the event that is feared; equivalent to the Latin nē , and in English often admitting of being replaced by that (without accompanying negative).

[OED]

LEO dict. isn't entirely helpful on this point.

Your first example is covered by OED sense 2 and could be replaced here by "that":

" ... for I dreaded that she should get some ..."

Your second example by sense 1a; it can be replaced here by "for fear that":

" ... taking care to smell and taste it, for fear that it, too, were ..."

(I believe you can translate "lest" in the second example with "auf dass es nicht ... .")

Thank you very much for your help!

I have now, to test myself, taken any other work, Wuthering Heights by Emily Brontë, and searched for the word "lest". Then this sentence appeared:

This was especially to be remarked if any one attempted to impose upon, or domineer over, his favourite: he was painfully jealous lest a word should be spoken amiss to him (…)

I assume that Rule No. 2 is also used here? The word "jealous" is the "verb of fearing", and "a word should be spoken amiss to him" would then be the "clause expressing the event that is feared".

So you could say: "he was painfully jealous that a word should be spoken amiss to him"?

Yes, exactly ;-)

And in Wuthering Heights Ch. 7:

"I removed the habit, and there shone forth beneath a grand plaid silk frock, white trousers, and burnished shoes; and, while her eyes sparkled joyfully when the dogs came bounding up to welcome her, she dared hardly touch them lest they should fawn upon her splendid garments."

P.S. 5 mins. later ...

I see your example in #2 also works as an example of the OED sense 1a ... Odd, it seems to me that both senses work here. I'll have to mull it over ... I don't have time right now.

This example (also Wuthering H. Ch. 7):

" ... and from that I went on to think of his fondness for Heathcliff, and his dread lest he should suffer neglect after death had removed him ... "

---can only be replaced by "that."