hi where are you from tell in comment
Sign language is a language, as it possess the most important characteristics of language: it serves communication, and everything that can be said in other languages, such as English, can be expressed in sign language too.
I believe the answer to your question is Sherlock Holmes is not convinced and believes there is a scientifically explanation. Remember Sherlock Holmes is a detective and is a logical rational man who doesn't believe in monsters. Hope this helps answers your question enjoy the rest of your day :)
