Unexpected string behaviour: txt = 'this' ' works'

[c d saunter]

I did a double take when debugging an error the other day.  My
problem was missing out a comma when building a list of strings.

Much to my surprise the offending code still executed to cause
problems later on:

>>> txt = 'this', 'works'
>>> print txt
('this', 'works')
# As expected
>>> txt = 'this' 'works'
>>> print txt
thisworks
# Eh?

I have never seen this behaviour before, but it works in Python 2.2.1
and 2.5.4 so I guess it's meant to be there.  I assume it is a feature
of the compiler.

Any thoughts?
Regards
Chris