During the restoration of the Tours Fine Art Museum, doctor Langston was requested toevaluate the factors liable to contribute to the deterioration of the principal works. It was also suggested, if the worst had already occurred and certain works had already fallen victim to the ravages of time, that Langston determine the exact causes. In spite of his advanced years, Langston buckled down to the job and a year later, he produced a detailed report on the question.