Coniine is a poisonous alkaloid found in poison hemlock and the yellow pitcher plant, and it contributes to hemlock’s unpleasant odor. Coniine was first synthesized by Albert Ladenburg in 1886, being the first of the alkaloids to be synthesized. It is a neurotoxin which disrupts the peripheral nervous system. Less than 0.2g is fatal to humans, with death caused by respiratory paralysis. Socrates was put to death by means of this poison in 399 BC.