This always made the students laugh, and with a twinkle of amusement at his own bright humour the physician prescribed some other drug than that which the student had suggested. When there were two cases of exactly the same sort and the student proposed the treatment which the physician had ordered for the first, Dr. Tyrell exercised considerable ingenuity in thinking of something else. Sometimes, knowing that in the dispensary they were worked off their legs and preferred to give the medicines which they had all ready, the good hospital mixtures which had been found by the experience of years to answer their purpose so well, he amused himself by writing an elaborate prescription.