If I eat a poisonous potato, it attacks my immune system and I die.
But if I poison a poisonous potato, then eat it, then I won't die because the potato is already dead and can't attack my immune system.
A women's knitters group is having a meeting, and they are all pregnant. They all talk about their pregnancies.
One woman says, "I'm taking vitamin C so my baby has a healthy immune system."
Another knitter says, "I'm taking folic acid to help my baby's brain."
Finally, one woman says, "I'm taking Thalidomide!"
All the women turn to her and say, "Thalidomide! Don't you know your baby could be born without arms?"
The woman shrugs her shoulders and says, "I don't know how to knit arms."
I only seem to get sick on weekdays. I must have a weekend immune system.
