McGonagall's cookies

[lewa8978]

No: HPFGUIDX 75244

One thing I noticed when reading OoP was McGonagall's insistance that 
Harry eat a cookie. I don't have my book handy, but I think this 
actually happens twice, and then later the tin of cookies is knocked 
over. Is there something important about Harry eating the cookies? 
Here's what I'm thinking: right around the time the cookies come up, 
there is a potions class where they discuss a calming potion. Is it 
possible that McGonagall has "laced" the cookies with something and 
that's why she pushes them on Harry? If I recall correctly, she even 
insists on making him take one for the road. Again, I don't have my 
book handy, so if I remember this incorrectly, please be kind.

Jen