When Marker went to Mexico City in January 1942, the U.S. Embassy advised him to leave immediately because of widespread anti-American sentiment fueled by World War II. Instead, Marker took a bus to Orizaba, changed to the local bus to Cordoba, and, on the way, recognized the stream described in the botany text. By the stream, he found a country store owned by Alberto Moreno, a native Mexican who did not speak English. Despite the language barrier, Moreno was enlisted to find some cabeza de negro. Although Marker had no plant-collecting permit, two large roots in bags soon were loaded on top of the bus to Orizaba. When Marker got there, the bags were gone, but he recovered the larger 50-pound root by bribing a local policeman.
Back at Penn State, Marker isolated diosgenin in satisfactory yield from part of the smuggled tuber. Because his research had been funded by Parke-Davis, Marker took the rest of his root to its laboratories in Detroit. There, he repeated his process in an attempt to persuade the company to commercialize it. However, Parke-Davis’s president refused, because he believed chemical work could not be done in Mexico. Marker’s efforts to interest other pharmaceutical houses also failed, and, by the fall of 1942, he was convinced the only path to success “was for me to do it myself.”
Marker returned to Veracruz and arranged with Moreno to collect and dry about 10 tons of cabeza de negro. In Mexico City, he found a man with a small-scale extractor, who extracted the roots with alcohol and evaporated the extract to a syrup. Next, in return for a third of the product, Marker arranged with a New York friend, Norman Applezweig, to use his laboratory to convert the syrup to progesterone. Marker finished with three kilos valued at $80 per gram, then the largest lot of progesterone ever produced.