Some Foods Explode in Your Stomach" - 24 Lessons in Scientific Eating (Everybody's Magazine, Nov 1915)
The pattern
This still is filed under If-then promise.
Define
A conditional contract: if you do this, you get that. The sentence can be tested against the reader's own case.
Mechanism
Specificity does the persuading. The if names the action. The then names the outcome. Hedging kills it.
Verdict
We can name both the action and the result without adjectives
Why it works
The headline takes a literal physical event and applies it to the reader's own body, which is a curiosity lead that is also a threat, so it is nearly impossible to leave unread. The retort illustration is the demonstration the claim needs: it shows a controlled experiment standing in for digestion, which lets a chemical assertion be pictured rather than proved. The synopsis column does the work a sample chapter would do today, converting an intangible course into 24 countable deliverables, while the testimonial column supplies names and street addresses for verification. Payment is deferred entirely, so the reader is only deciding whether to look, and the send-no-money mechanic makes the coupon feel like a request rather than a purchase.
Steal this when
Use this when you sell information and the reader does not yet believe he has the problem: open on a physical, shocking image of the hidden mechanism, itemise the contents so the intangible becomes countable, and remove payment from the first step entirely.