Trouble with hide('slide');

Trouble with hide('slide');

So I suspect I'm doing something really stupid, but...

I have the following line of code:

$('.' + class).hide('slide');

Which works as expected, sliding the object to the top left.

After that, I tried

$('.' + class).hide('slide', { direction: 'left' });

And it failed. I tried copying the exact code from the jQuery documentation and that failed. I tried including a 500 at the end for a time and that didn't work either. Am I missing a detail here? Hopefully someone can help me figure out where I'm failing.