Alice Mitchell -- Australia
Between 1900 and 1906 Mitchell, who was employed as a baby nurse, 
was suspected of killing 37 babies, either through starvation or neglect. 


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

http://www.aic.gov.au/publications/tandi/ti25.pdf

http://www.publicdebate.com.au/cgi-bin/cgimes?issue=1&post=323&c=1615