American Cyanamid biochemist Robert White-Stevens and former Cyanamid chemist Thomas Jukes were among the most aggressive critics, especially of Carson's analysis of DDT. According to White-Stevens, "If man were to follow the teachings of Miss Carson, we would return to the Dark Ages, and the insects and diseases and vermin would once again inherit the earth." Others went further, attacking Carson's scientific credentials (because her training was in marine biology rather than biochemistry) and her personal character. White-Stevens labeled her "...a fanatic defender of the cult of the balance of nature," while former U.S. Secretary of Agriculture Ezra Taft Benson, in a letter to former President Dwight D. Eisenhower, reportedly concluded that because she was unmarried despite being physically attractive, she was "probably a Communist."