Nearly everybody who is searching for spirochetes in bloodfilms or with darkfield has passed through the stage where he thinks a pseudo-spirochete to be a spirochete, but once familiar with the appearance of real living leptospirae, no confusion is possible.
Pseudo-spirochetes have been described by many authors and since the discovery of the spirochetosis ictero-hemorrhagica or the Weil's disease and since the use of the darkfield, the question has been raised again whether or not investigators have met with real living organisms.
So does Milton W. Hall in search of spirochetes in dengue fever. He gives a very good reproduction of pseudo-spirochetes and cites an accurate description of the forms in native blood by Schulz.
A very good reproduction of pseudo-spirochetes is also given by Pons (Bulletin de la Societé de Pathologique Exotique, T. XVII, 1924, p. 307).
Without any doubt most of the pseudo-spirochetes are protoplasm extrusions from red blood corpuscles as one may see in darkfield in blood kept for some time undiluted or mixed with samline or with Ringer's fluid.