what happens to renfield in chapters 12-14

Seward's assistant Patrick Hennessey reports the latest news on Renfield. On seeing two men who are carrying boxes of earth to the Carfax estate, Renfield escapes and attacks them before he is subdued and brought back to the asylum. Renfield's licking of Seward's blood suggests why he has given up eating flies‹his desire to consume life has found a new model in the vampire. He now seeks to serve his master and also to imitate him.