 Wu's hypothesis was also advanced independently in 1936 by Mirsky and Linus Pauling.Nevertheless, protein scientists could not exclude the possibility that denaturation corresponded to a "chemical" change in the protein structure, a hypothesis that was considered a (distant) possibility until the 1950s.X-ray crystallography had just begun as a discipline in 1911, and had advanced relatively rapidly from simple salt crystals to crystals of complex molecules such as cholesterol.