Although Michel Chevreul's career was distinguished by his skills in many different fields, his research on organic substances stands as his greatest achievement. It led to development of new candles and better soap-making processes and even gave science its first clue as to the cause of diabetes.

When Chevreul began studying animal fats in 1809, organic chemistry was in its infancy. In effect, he established the entire branch of chemistry that covers the nature of fats, and he proved that organic substances obey the same laws as inorganic chemicals. With few rules to go by, Chevreul was able to isolate and name several fatty acids, including stearic, palmitic, and oleic--the three most important components of fats and oils. In doing so, he introduced new analytical techniques such as using the melting point of a substance to determine its identity and purity. By 1816, he had found that all animal fats...