The contribution of Dr. Mary Walker towards myasthenia gravis and periodic paralysis whilst working in poor law hospitals in London.

Dr. Mary Walker discovered in 1934 that physostigmine and Prostigmin temporarily restored muscle function in patients with myasthenia gravis. In the next five years, Dr. Walker and colleagues provided clinical evidence for the weakness of myasthenia gravis being caused by a "disturbance of transmission of excitation from motor nerve to voluntary muscle presumably caused by a deficiency of acetylcholine. Physostigmine (or Prostigmin) compensated for the lack of acetylcholine by delaying its destruction." Dr. Walker and colleagues also described the association between familial periodic paralysis and hypokalaemia.