Most often styling himself Doctor Katterfelto, he initially leapt to fame by treating patients during the influenza epidemic of 1782. For the next couple of years he gave numerous didactic performances to metropolitan audiences, and became a household name. Charging from 1s. to 3s. a seat, he gave different three-hour shows each night of the week.The biography notes that although Katterfelto allegedly delighted George III and other royals in 1784, life was hard. A caricature shows him clutching bags of gold but
he spent most of the rest of his life striving to support his wife and children as an itinerant provincial entertainer". ... Announcing his arrival with long series of advertisements in local papers, Katterfelto travelled all over England. He lectured successfully at Birmingham in 1792, but was gaoled in at least two other towns as a vagrant and an impostor.Katterfelto
compiled a great variety of flamboyant newspaper advertisements and wall posters, many of them incorporating long poems. Their two major themes were his fame as an international freemason with secret knowledge of occult mysteries and his expertise as a natural philosopher. Correspondingly, his two renowned props were his necromantic black cat and his solar microscope, a device which projected magnified displays onto a white surface for public viewing. By revealing thousands of 'insects' writhing in a drop of water, he persuaded Londoners terrified of catching influenza to purchase his patent medicine at 5s. a bottle. In addition, his diverse equipment included a lecturer's standard natural philosophical apparatus-some of it quite expensive-such as compasses and globes, an orrery, a telescope, an air pump, and an electrical machine. To attract his declining audiences he proclaimed ever more exotic devices, including a perpetual-motion machine, a magnetic copying apparatus, and sympathetical clocks. One celebrated trick entailed lifting his daughter to the ceiling by using a large magnet for attracting a steel helmet on her head.