Verity and .pdf files

I am starting out using Verity new. My questions is, when I create a collection, does Verity read the actual .pdf content? If I have a .pdf file that pertains to a particular drug for high blood pressure will the collection contain the .pdf content is the drug name is mentioned in it? If not, what exactly does the collection index when it is indexing a folder full of .pdf files?

Thanks,