Citing medium of access for a book in MLA I'm trying to write an essay with the following MLA citation in the bibliography:


  Hoffman, Conrad. In the Prison Camps of Germany: A Narrative of "Y" Service among Prisoners of War. New York: Association,  1920. Print.


After reviewing it, my teacher posted the following comment:


  Be sure to include the medium of access.


The resource in question was virtualized via Google. How do I represent the medium of access in an MLA citation for a virtualized book?
According to the Purdue Online Writing Lab, which is usually a good source for such things, journal articles that are available both online and in print should be cited based on which medium you actually used to access the article:


  Article in an Online Scholarly Journal That Also Appears in Print
  
  Cite articles in online scholarly journals that also appear in print as you would a scholarly journal in print, including the page range of the article. Provide the medium of publication that you used (in this case, Web) and the date of access.


I would thus anticipate that the same principle should be applied to a scanned book.  Even though the original was generated long before the web existed, you accessed it through the web today, and since you are recording publication medium, that's the publication medium by which it was actually delivered to you.