I had forgotten that in the books, Holmes tested the tablets on a terrier,conclusively proving the nature of the poison, whereas in the show he just throws it to the ground in a rage, never knowing if he was right. I feel the literary Holmes would never have allowed doubt to plague him, so I wonder why the writers ddecided to let this stand in the show. Will this Sherlock prove less confident in the long run? Were they too scared to show animal cruelty? I just have a mental image of writers and producers discussing whether they would get away with depicting the poisoning of a small dog on primetime. Humans dying, no problem. Man's best friend? No chance.