At my previous place of employment, we used to flirt every year or so with the idea of taking out a subscription to Chadwyck Healey’s index to the Patrologia Latina. Each year we’d experience financial vertigo as we contemplated the subscription and would step sadly back from the precipice. Although an index to the whole Patrologia would be very useful, most of us could save up those hard-to-find references for our next trip to a research library filthy-rich enough to afford such luxuries.
In the meanwhile, I discovered what I now call the “poor man’s patrologia.” It’s the fantastic, but nevertheless faintly unhinged website called Documenta catholica omnia. It has nearly everything: the patrologia latina, bits of the patrologia graeca, and even Mansi’s Concilia. What a service!
My tip for impoverished scholars, or those like me who are working in remote and impoverished institutions, is to use google/google books to locate your obscure reference. Then use that reference to download a transcription of the relevant volume of the patrologia from the Documenta website.
Then, when you get a chance to visit a filthy-rich research library, you can cross check against the real volumes of the patrologia.
As to the faintly unhinged bit, the Documenta site has two charmingly broadminded links to documents produced by non-Catholic authors.
If you’re looking for something Protestant, Jewish or Muslim, you’ll find it under De caeteris opinionibus superstitionibusque (On other opinions and superstitions). We have advanced a bit on the 17th century in that “Calvinists” are filed with “schismatics” rather than “heretics.”
With any luck, in about 250 years time, the link will be updated to embrace them all as fratres seiuncti.
Other unpleasant opinions (Masons, Communists, Enlightenment thinkers) are lumped under De illis qui Deum Ecclesiamque suam in odium habuerunt (On those who hate God and his church).
But, perhaps because of the service they’ve done for magistri pauperi et remoti everywhere, the Catholic triumphalism can be overlooked.