The chemical curare is used as a muscle relaxant. It is derived from South 
American plants such as Chondrodendron tomentosum. Given intravenously
it causes diplopia and ptosis. Paralysis of the extraocular muscles also reduces 
the intraocular pressure.  Harold R. Griffith was the first anaesthetist to use
curare on patients to reduce spasm during surgery in his Montreal hospital.