- I'm afraid I'll have to put you to sleep until we reach the city, Batgirl.
- So you won't learn the location of the Batcave.

9 seconds sound clip from Batman (1966) - The Entrancing Dr. Cassandra (S3E25) TV Series.

You can hear this line at 00:18:34 in the Blu-ray version of the movie.

Quote context

[...]

- According to this, they should all be in the basement of Mortar and Pestle Building on Abracadabra Alley.

- But how can we get there? Isn't the Batmobile still parked in front of Spiffany's Jewelry?

- Look. Here it comes now.

- Now, how in the world did you manage that?

- There's no time for that now, Batgirl. To the alley.

- I'm afraid I'll have to put you to sleep until we reach the city, Batgirl.

- So you won't learn the location of the Batcave.

- All right, Batman.

- Guard your face, Robin.

- You know something? She looks very pretty when she's asleep.

- I thought you might eventually notice that.

- That single statement indicates to me the first oncoming thrust of manhood, old churn.

[...]