Martha Rendell 

Murdered three of her defacto's children by swabbing their 
throats with hydrochloric acid. She beat them severely and 
insisted they call her "Mother". The medicos thought the 
children had died of diptheria and it was only when an older 
boy ran away that the truth began to emerge. Rendell was the 
last woman hanged in Western Australia.

http://www.redbackwebs.com.au/cufflinks/police/serial.html#Rendell

http://home.talkcity.com/SpiritCir/d1zzy/MarthaRendell.html