Sam Johnson 
Tetrahydrocannabinol, also known as delta-9-tetrahydrocannabinol (Δ-THC), is the principal psychoactive constituent of the cannabis plant. First isolated in 1964, in its pure form, by Israeli scientists Raphael Mechoulam, Yechiel Gaoni and colleagues at the Hebrew University of Jerusalem, it is a glassy solid when cold, and becomes viscous and sticky if warmed. A pharmaceutical formulation of THC, known by its INN dronabinol, is available by prescription in the U.S.
