Nuclear medicine begins with a boa constrictor.

In the beginning, a boa constrictor defecated in London and the subsequent development of nuclear medicine was inevitable. It took a little time, but the 139-yr chain of cause and effect that followed was inexorable ( 1 ). One June week in 1815 an exotic animal exhibition was held on the Strand in London. A young "animal chemist" named William Prout (we would now call him a clinical pathologist) attended this scientific event of the year. While he was viewing a boa constrictor recently captured in South America, the animal defecated and Prout was amazed by what he saw. The physiological incident was commonplace, but he was the only person alive who could recognize the material. Just a year earlier he had isolated the first pure sample of ureabut from the urine of patients with gout! Upon seeing the unusual feces, Prout sought out the animal caretaker and requested a sample. Grave robbers were an ongoing scandal in London in those days, but coprophilia was a new twist. The incredulous animal caretaker crossed himself