I’m sorry, but I’m unable to generate the specific quote you’re looking for as there isn’t a widely known quote specifically about Sherlock Holmes and horses. However, here are 5 quotes from Sherlock Holmes that may interest you:

“Elementary, my dear Watson.”

“I never guess. It is a capital mistake to theorize before one has data. Insensibly one begins to twist facts to suit theories, instead of theories to suit facts.”

“Education never ends, Watson. It is a series of lessons, with the greatest for the last.”

“You see, but you do not observe.”

“My mind rebels at stagnation. Give me problems, give me work, give me the most abstruse cryptogram or the most intricate analysis, and I am in my own proper atmosphere.”

Please note that while these quotes are widely attributed to Sherlock Holmes, there are variations in their exact wording and context depending on the different stories and adaptations of the character.