By the early 1930s, over 500 men had been treated in France by his rejuvenation technique (including Voronoff's younger brother Georges), and thousands more around the world, such as in a special clinic set up in Algiers. Noteworthy people who had the surgery included Harold McCormick, chairman of the board of International Harvester Company. To cope with the demand for the operation, Voronoff set up his own monkey farm in Ventimiglia, on the Italian Riviera, employing a former circus-animal keeper to run it. French-born U.S. coloratura soprano Lily Pons was a frequent visitor to the farm. With his growing wealth, Voronoff occupied the whole of the first floor of one of Paris's most expensive hotels, surrounded by a retinue of chauffeurs, valets, personal secretaries and two mistresses.