There may be in the cup
A spider steeped, and one may drink, depart,
And yet partake no venom, for his knowledge
Is not infected: but if one present
Th’ abhorred ingredient to his eye, make known
How he hath drunk, he cracks his gorge, his sides,
With violent hefts. I have drunk,
and seen the spider.
– William Shakespeare
The Winter’s Tale, Act 2, Scene 1.