# XVIII explained — Monsieur Lecoq

> Chapter companion for Monsieur Lecoq by Émile Gaboriau.

## What happens

Lecoq establishes a secret observation post in a loft above the prisoner May's cell, vowing to watch him day and night to uncover his true identity. Despite Gevrol's skepticism, Lecoq compares his method to that of naturalists studying insects. He intercepts a coded message hidden in a bread pellet, and with the help of M. Segmuller and the prison governor, deduces that the cipher uses a book cipher based on Beranger's songs, successfully decoding the first part of the message.

## Themes in this chapter

### Deduction and Scientific Observation

Lecoq applies a naturalist's method of close observation to study the prisoner, believing that patient surveillance will reveal the truth.

### Deception and Disguise

The prisoner May maintains a facade of cheerfulness and normalcy, while secretly communicating via a coded message hidden in bread.

### Ambition and Professional Rivalry

Lecoq's determination to succeed is fueled by his rivalry with Gevrol, who mocks his methods but fears being proven wrong.

## Character check-ins

### Monsieur Lecoq

Sets up a hidden observation post in the loft, resolves to watch the prisoner constantly, and deciphers the coded message using Beranger's songs.

### Gevrol

Scoffs at Lecoq's methods, comparing him to a naturalist watching insects, but is secretly troubled by Lecoq's confidence.

### M. Segmuller

The magistrate who works with Lecoq, grows anxious and loses appetite over the case, but remains determined to solve the enigma.

### Father Absinthe

Mentioned as the one who will bring Lecoq his meals and relieve him during his vigil.

### Joseph Couturier

Referenced indirectly as the prisoner May, who is the subject of Lecoq's surveillance and the sender of the coded note.

## Key lines

> I shall be present if ever his will fails him, if, believing himself alone, he lets his mask fall, or forgets his part for an instant, if an indiscreet word escapes him in his sleep, if his despair elicits a groan, a gesture, or a look—I shall be there to take note of it.

Lecoq vows to be there whenever the prisoner's resolve weakens, hoping to catch him off guard when he drops his disguise.

_Highlights Lecoq's relentless surveillance strategy._

> What they can do with an insect, I will do with a man!

Lecoq compares his method to that of naturalists studying insects, asserting he will apply the same patience to understanding the prisoner.

_Illustrates Lecoq's scientific approach to detective work._

> If I am not mistaken, the prisoner and his accomplice have adopted a very simple system called the double book-cipher.

Lecoq identifies the coded message as using a book cipher based on a shared book, which he deduces is Beranger's songs.

_Shows Lecoq's skill in cryptography and deduction._

## Links

- HTML: https://www.betterreads.online/discover/monsieur_lecoq_se/chapters/xviii
- Book: https://www.betterreads.online/discover/monsieur_lecoq_se
- All chapters: https://www.betterreads.online/discover/monsieur_lecoq_se/chapters