Otto Diels

"It will rightly be asked: What is the synthetic principle on which this obviously highly important product of y-methylcyclopentenophenanthrene is built up in nature, and why is it that this particular type which, as founda tion of many substances indispensable to life and of extreme physiological and biological importance, plays such a vital role in the vegetable and animal kingdoms? However, the time has not yet come when we can give an answer to questions so fundamental and so important to an understanding of the workings of Nature. But I am firmly convinced that this problem - like all others - will eventually be solved."