The title of this cat painting is "A Fascinating Tail." It is easier to see in this high-res copy but that tail, is of a rodent in a trap. Ruskin's sample is less sentimental than I thought at first.
We learn here that :
In 1875...[Couldery] attracted the attention of the art critic John Ruskin who commented that one of his paintings entitled ’ A Fascinating Tail’ exhibited at The Royal Academy was “ quite the most skilful piece of minute and Dureresque painting in the exhibition, which could not be rightly seen without a lens and unsurpassable in its depiction of kitten meditation"
More of these kittens can be seen here though we don't know Ruskin ever saw Couldery's other art. He probably did: Couldery exhibited at least twenty paintings at the Royal Academy.