PubMed Central, in collaboration with the Wellcome Trust, has digitized a number of nineteenth and twentieth century medical journals, including The British Medical Journal. The content of these, along with more recent publications, can be searched in PubMed Central.
Archive.org. This is a repository where many libraries place digital versions of works they digitize. You may be interested in browsing the items that the Osler Library of the History of Medicine has added; this is updated as content increases. Items in Archive.org are indexed and linked in McGill's library catalogue.
Counseling and Psychotherapy Transcripts Database of 2,000+ transcripts of counseling and therapy sessions and 44,000 pages of first-person narratives illuminating the experience of mental illness and treatment. Also includes secondary reference works material.