The subject is sponge because that is what is the main point of the sentence is.
Answer:
Sherlock Holmes kept his tobacco in the toe of his Persian slipper.
Explanation:
The famous character of Sherlock Holmes is a creation of Arthur Conan Doyle, a British writer. His fictional character of Sherlock Holmes is famous worldwide, with it being made into movies with numerous titles.
One of the most significant characterization of the image of "Sherlock Holes" is his tobacco pipe, or the Calabash which has become one with his character. This pipe or tobacco is seen alongside him always, becoming part of his own persona. In "The Adventures of The Musgrave Ritual", we see his partner Dr. Watson mentioning that Holmes used to keep "his tobacco in the toe end of a Persian slipper". This particular item or accessory of Holmes is also his distinguishing feature in the story, for it gives him a unique entity of his own.
A good reference for this is "The Five I's of Romanticism"
Imagination
Intuition
Individuality
Idealism
&
Inspiration
A. similes use like or as and metaphors do not
