Answer:
What shows that the narrator is afraid of the moral and ethical consequences of his experiment is seen in the phrases "the beauty of the dream vanished" and "breathless horror and disgust filled my heart".
An excerpt from the text:
"I had desired it with an ardour that far exceeded moderation; but now that I have finished, the beauty of the dream vanished, breathless horror and disgust filled my heart"
Step-by-step explanation:
The narrator clearly stated that when he should have desired an ardour due his accomplishments, he rather had horror, disgust and was unable to sleep. This tells us that the narrator was experiencing the consequences of what he did. Something wasn't right in his experiment and in the process employed to achieve that feat.
What he did began to haunt him; no rest and peace of mind for him. Actually, he was reaping the consequences of what he did.