bedpan vs chemical toilet

bedpan

noun
  • A pan used for urination and defecation while in bed, now usually for reasons of medical necessity or convenience. 

chemical toilet

noun
  • A toilet or chamber pot which treats waste in place with chemical disinfectants and deodorizers, as in airplane lavatories. 

How often have the words bedpan and chemical toilet occurred in a corpus of books? (source: Google Ngram Viewer )