Jerome's Answer:
In the book "Three Men in a Boat," Jerome states that Montmorency's ambition in life is to kill rats. He describes Montmorency as a dog with a strong desire to hunt and kill rats, and believes that Montmorency truly believes he is a great rat-hunter.

My Opinion on Montmorency:
In my opinion, Montmorency is an interesting character. He adds a sense of adventure and excitement to the story, as well as some humor. His ambition to kill rats may seem trivial or mundane, but it reflects his natural instincts as a dog.

Montmorency as a Rat-Hunter:
Montmorency's ambition to kill rats highlights his hunting instincts and his desire to fulfill his natural role as a dog. Dogs are known for their hunting abilities, and rats are often seen as pests that need to be eliminated. Montmorency's determination to chase and kill rats showcases his instincts and his need to fulfill his purpose as a dog.

Montmorency as a Comedic Relief:
Montmorency's character also serves as a source of comedic relief in the book. His unsuccessful attempts to catch rats, his encounters with other animals, and his mischievous behavior provide laughter and entertainment for the readers. Montmorency's clumsiness and his inability to successfully fulfill his ambition add a lighthearted element to the story.

Montmorency's Role in the Group:
Furthermore, Montmorency's presence in the group of three men adds a dynamic element to their adventures. He is a loyal companion and a source of comfort for the men. His energy and enthusiasm bring a sense of liveliness to their journey. Despite his flaws and his obsession with rats, Montmorency is an integral part of the group, contributing to the overall narrative and the bonding between the characters.

In conclusion, Montmorency's ambition to kill rats showcases his natural instincts as a dog and adds a humorous element to the story. He is a beloved character who brings excitement, comedy, and companionship to the group of three men.