Answer:
He was enthusiastic about unleashing his theory of natural selection on the world as soon as he thought of it.
Explanation:
He know that his finding at that tie would be considered as controversial since it's directly oppose the teaching of the churches which adopted by most people at that time. It's hard to feel enthusiastic knowing that you will face massive backlash for your finding.
and he's right.
As soon as he release the theory, Many people start to attack and misrepresented his credibility. It took decades before more people start to actually accept the theory of natural selection.