"Someone has indeed summoned a non-animal Patronus before," Flitwick replied. "As far as I know, someone's Patronus was a ladybug. And Minerva has more than one Patronus as well."
"Really?" Pomona said in surprise.
"Having multiple Patronuses makes communication easier, or so she told me." Flitwick gave a wry smile. "It seems she has secrets beyond being an ordinary teacher."
Pomona did not tell Flitwick about the Order of the Phoenix. As a neutral Head of House with no small amount of power, there were some things he was better off not knowing.
"Every animal can sense that it has only one soul." Flitwick did not dwell on the subject and continued, "Their composition is not as complex as that of humans. After they die, they become sprites and exist within nature."
"What about human souls?" Pomona asked.
"That is a complicated question." Flitwick sighed. "They believe their souls are indestructible. Some religions even believe that souls can reincarnate, passing from one body into another."
"You don't believe that?" Pomona asked.
"You saw Professor Quirrell. If an animal carried an unfamiliar soul that did not belong to it, it would not sense it, nor would that soul take over the animal's form. But humans can sense it. When an outside soul occupies a body according to its natural inclination, the original soul resists."
"How do you know that?" Pomona asked.
"How do you know?" Flitwick asked.
They smiled at each other.
"I discussed this subject with the Headmaster. So far, we have not found any case of an animal carrying another soul. It is only a hypothesis. In human mythology, the stag is the guardian of the forest. Perhaps Mr. Potter's Patronus is so powerful because this forest is using him to drive away those Dementors from the Land of