This picture is credited as being 1926 and shows Houdini giving a lecture, likely related to spiritualism. He has what look like Spirit Slates in his hands and is addressing what appears to be an audience volunteer. The men in the photo look too old to be college students, so this is not Houdini's famous final lecture at McGill University. But this image gives us a taste of what that may have looked like.
UPDATE: It appears the original source for this image is the Library of Congress.