That gunky stuff was known as ectoplasm, a paranormal Goo From Beyond. Ectoplasm appeared in seances and spiritualist photographs around the turn of the century. This Goo From Beyond is, of course, a parlor trick. This photo seems to show tissue paper with photos cut from magazines.
Ectoplasm would issue from the bodily orifices of the medium during the seance. It normally came from the nose or mouth, but could also come out the ears, eyes, nipples, and, as the photo below suggests, regions further to the South.
Ectoplasm has an aversion to light and thus only appears in the darkened rooms of the seance. This is convenient in that it keeps observers from getting to close a look, although these flash photos must have turned at least a few people into skeptics.
Spiritualism really kicked off in the United States due to the appalling loss of life during the Civil War. For more on that, check out my article Spiritualism during the American Civil War. It still exists as a movement today, although ectoplasm has fallen out of favor. A pity. I really like to see people sneeze up spirits.
Top photo courtesy Wikimedia Commons. Bottom photo from the fun Fortean blog Who Forted?, which has a lengthy quote from a Spiritualist "explaining" ectoplasm.
