Loosing the content of received emails on IPad2

Since some days ago I remarked that the body of my received emails was diseapearing.
What I see is "From", "To", "Object" and the date...

I can see the body or text of my mail only if I do "Transfer to".

In this case eventually images are not present. This is an IPad2, but I suppose that the case should be the same with IPad3.
May be I, by mistake, I modified something in the configuration menu, but what? (note: I actually use 7 e-mail boxes with 3 different providers + icloud... could it be the reason of it)
Thanks for help!
Regards from today's rainy Switzerland!