In the mid 19th Century the introduction of horses to carry fire trucks instead of men vastly improved their response time to putting out fires. However horses were notoriously afraid of fire (and rightly so) but this is where Dalmatians come into play.
Dalmatians were known to be the official dog of the fire house, they had a peculiar presence that was able to calm the horses down and provide a comforting influence when around the fires. They would form strong bonds with the horses and scare away anything that might spook them.