Alexandra Petri is a Washington Post columnist offering a lighter take on the news and opinions of the day. Petri is the author of "A.P.'s US History: Important American Documents (I Made Up)" and ...

Petri dishes are shallow, cylindrical, lidded dishes that are used to culture cells. They are sometimes called Petri plates or cell culture dishes. In biology experiments and studies, Petri dishes are ...

It has now been told it can dock in Cambodia. Cruise ships have for years been referred to as "floating Petri dishes" - places ripe for the exchange of germs, and the spreading of illness.

Michelle Petri, MD is a Professor of Medicine at the Johns Hopkins University School of Medicine. She attended medical school at Harvard University and fulfilled her internal medicine residency at the ...