Hi doctortornface
Quote: "Jazz, Blues - So what´s the difference".
Both styles/directions in music belong to/were evolved in the american music history from a very black, in every sense of the word black, part of american history.
First came the negro spirituls, songs sung on the cotten fields in the south of the USA by african american slaves, imported from Africa to work on the fields, then the blues and finally jazz.
Difficult to go further in to it without getting in to politics and racial matters, which I never do. Beside this, it is not proper on this peaceful website. But you might try Wiki..for a more detailed definition.
Best regards,
intet-at-tabe