question about foreach and associate array

I have the following construct:

     $arg['textarea']['body']="Hello";

      foreach($arg['textarea'] as $row)
      {

echo $row['body']."<br/>"; echo $arg['textarea']['body']."<br/>";

      }

I would expect both of them to output "Hello" but only the second does. The first outputs "H". I thought I have done this before. Can anybody tell me why this won't work? thanks, jonathan