He would go on like a man swimming under water; he would put his handkerchief over his face, and begin to cough and choke; and then, if he were still obstinate, he would find his head beginning to ring, and the veins in his forehead to throb, until finally he would be assailed by an overpowering blast of ammonia fumes, and would turn and run for his life, and come out half-dazed.