Cruel Anatomist How does this work?

[Darkthorne68]

Normally most things I can figure out or get the general gist of. This depending on how it's translated could mean a slew of different results.

"At 3rd level, a vivisectionist may use his Knowledge (nature) skill bonus in place of his Heal skill bonus"

Int 14 +2 Bonus
Wisdom 12 +1 Bonus

Know. Nature 3 ranks + class (3) + Int (2) = 8
Heal 3 ranks + class (3) + Wis (1) = 7

What numbers are being added or replaced to the Heal total from the Know. Nature numbers?
Thanks

[Seranov]

Instead of rolling your Heal skill, you may roll Knowledge (Nature). It's why putting points in the Heal skill as a Vivisectionist is not a good idea, as you'll never have to use them after level 3.

[Darkthorne68]

Thanks.
It was the "skill bonus" that was throwing me. I think "skill total" would have been more clear to me.