A note from history: two pioneering chemists, three hundred years apart.

The use of chemicals gradually increased from prehistoric time to the fourth century A.D. when alchemy was introduced. Alchemy was a branch of chemistry that attempted to transform base metals (eg, lead, copper, and zinc) to precious metals (eg, silver and gold) [1]. Alchemists pursued this futile goal with secretive stubbornness for over a thousand years, to the detriment of chemistry as a whole. The fact that chemistry established its scientific reputation at the expense of alchemy is largely due to one person, Paracelsus (1493-1541) (Fig. 1). Parcelsus was a contemporary of Nicolaus Copernicus (1473-1543) and was born in the year that Christopher Columbus (1451-1506) returned from his first voyage to the New World. During his student years at the University of Basel in his native Switzerland, Paracelsus’ initial interest was in mining and metallurgy, but he soon developed a serious interest in medicinal chemistry. He was an independent thinker and rejected the Greco-Roman Galenian humoral doctrine [2]. He did not accept authority and never settled long at one place. He crisscrossed Europe under the assumed name, Paracelsus, which means “equal with Celsus” (25 BC-AD 50), the eminent Roman physician [3]. Fig. 1. Paracelsus (1493 – 1541) Fig. 2. Paul Ehrlich (1854 – 1915)