Among the curious incidents in the lives and careers of Sherlock Holmes and Dr. Watson, surely none is more obscure than the matter of Dr. Watson's bull pup.
In the initial contact between Holmes and Watson, as related in A Study in Scarlet, Watson informed Holmes (or, perhaps it should be said, confessed to Holmes), "I keep a bull pup." And that, it seems, is the last we hear of the dog.
Holmes did not object to Watson having the dog in their lodgings, but we hear no more of it. Or do we? Was Watson's bull pup in fact the terrier upon which Holmes performed his experiment with the poisoned pill? If this is so, let us first dispose of any doubt concerning the use of the terms "bull pup" and "terrier" to describe the same dog. It is common knowledge that Dr. Watson was rather distressingly lax in his terms. Let us concede that this laxity extended to the dog in this case. Then let us consider the assumption that the dog was in fact the pet of Mrs. Hudson and not of Watson. Is there any basis for this? No.