I'm afraid the end may be rather terrible. The effect of the drugs will die with him. His body will become visible as life goes.
8 seconds sound clip from the The Invisible Man (1933) movie soundboard.
You can hear this line at 01:09:24.085 in the Blu-ray version of the movie.
Quote context
[...]
- Yes. I had a message to come immediately.
- Towards dawn this morning, he grew quiet.
- He called the name of a girl. I understand your daughter.
- Bullet passed through both lungs. It's impossible to treat the wound.
- Do you think your daughter could bear to go to him?
- I knew you would come to me, Flora.
- I wanted to come back to you.
[...]