- The first law of human nature is self-preservation, right?
- I suppose so.

6 seconds sound clip from the The Doctor Prescribed Death (Suspense) classic radio play.

You can hear this line at 00:07:22 in the radio play.

Quote context

[...]

- I meant I wasn't broke to the point of being hungry. I have a few dollars.

- But you suggested help for someone in larger turn.

- Yes, I did.

- Who is the loved one?

- My mother.

- You are her only means of support?

- Yes.

- And you intend to kill yourself?

- Yes.

- That's being selfish, isn't it?

- Selfish?

- Yes, you are concentrating solely on self.

- You think so?

- What else?

- The first law of human nature is self-preservation, right?

- I suppose so.

- The second law is the preservation of family.

- So you decide to deny the first law and destroy yourself.

- Into the consequence, deny the second and leave your mother alone and in need.

- You indicate a form of insanity.

[...]