What happened to the Sheep Professor in July of 1935 in the novel, A Wild Sheep Chase?

In July of 1935, he left on horseback for a study of the land and did not return for a week. He claimed he had been lost, and in reality had gotten lost, fallen asleep in a cave, and been inhabited by the sheep. He acts only as a transport for the sheep, and a year later, the sheep leaves him.