syphilis vs tabes dorsalis

syphilis

noun
  • A disease spread via sexual activity, caused by the bacterium Treponema pallidum. 

tabes dorsalis

noun
  • neurosyphilis in the form of such degeneration. 

  • tabes of the back; a degeneration of the sensory neurons of the spinal cord carrying afferent information. 

How often have the words syphilis and tabes dorsalis occurred in a corpus of books? (source: Google Ngram Viewer )