James parkinson on essay on shaking palsy

James Parkinsons essay on shaking palsy was published in 1817 is often considered to be his greatest contribution to medicine.The study is based on six cases some never examined but obsedved by him on streats.
He observed and differentiated tremor in PD from epilepsy,alcohol and caffine use.he did not discuss rigidity in his original cases.These distinctions were later added byTrousseau in is fifteenth lecture in clinical medicine