The character of "Juggle-Fred" appears only once in Karl May's writings. Juggle-Fred emerged in the story "The Ghost of Llano Estacado" published first in 1888.
"Have a close look at him, in particular his eyes, which have different colour. He is 'two-eyed'." This description preceded Juggle-Fred's arrival on the scene. This is how Karl May described the man: " [He was] of striking appearance. The first thing which one would notice on him, was a considerable hump, which spoiled his otherwise well-structured figure. His body was of middle height and of very strong build, not of a short torso, narrow chest and long arms, as it seems to be the case with most humpbacks. His round, full, clean shaven face was deeply suntanned, however terribly marked on the left side, as if some time ago an awful wound would have been badly stitched together. And in a very strange way his eyes were quite strikingly of different colour, the left was of beautiful sky blue, whereas the right was of the deepest black … If this man would not have the hump, his appearance would be of pleasing powerfulness, even perhaps impressive."
A rather forceful attempt to psychoanalyze Juggle-Fred appeared in 1983. Apart from other deductions, according to the author of the paper the dark eye was supposed to symbolize the prairie man. The blue eye should have been a positive representation of Karl May's character. Juggle-Fred should have represented the way Karl May dealt with his past 'crimes': "In Juggle-Fred are therefore incorporated the no good character features".
More informative is another paper "The Man with the Blue Eye". When Karl May was the editor of "Schacht und Hütte" in 1875-76, he mentioned in No. 21 a group of 760.000 German schoolchildren where the colour of the skin, eyes and hair was recorded. From amongst them 287.000 were found to have grey eyes, 224.000 had blue eyes, 255.000 brown, 450 black, 3 red, and one had one eye blue and the other eye was brown.
People with two different coloured eyes have been observed in the past. However it was a Dutch ophthalmologist, Dr. Petrus Johannes Waardenburg (1886-1979), who noticed that people with different coloured eyes frequently had hearing problems. He went on to study other characteristics of the syndrome, and described in 1951 what is now named after him - the Waardenburg Syndrome.
The Waardenburg syndrome (WS) is a genetic defect, inherited in a dominant fashion. The WS gene affects the body in three primary ways: (1) pigmentation (colouring) of the skin, hair and eyes, (2) hearing, and (3) the facial structure.
The most noticeable effect is the two different coloured eyes (heterochromia irides). Usually one eye is brown and the other is pale or bright blue. However not everyone who carries the gene has two different coloured eyes. Often is seen a white forelock (poliosis), a patch of white hair starting at the front of the head and extending backwards. The gene carriers become prematurely grey, in their twenties or early thirties. Sometimes even children as early as seven years old have grey hair, eyelashes and eyebrows.
Deafness appears in about 50%, i.e. at least half of those with the gene have no hearing problems. People with WS have a certain kind of look noticeable to the trained eye, but not so unusual that it is noted by the average person. The main feature is that the eyes seem to be more widely spaced than usual. They only appear so because the part of the face between the eyes is broader. There is a broad nasal bridge with lacking prominence of the frontonasal bridge. Also a displacement of the fold of the eyelids could be present, a lateral displacement of the inner canthus of each eye (Dystopia canthorum).
Waardenburg syndrome is subdivided into type 1 and 2 on the basis whether the displacement of the eyelid folds is present. However there exists a type 3, called Klein - Waardenburg syndrome (type 3). This type is characterized by upper limb abnormalities, an upper limb - pectoral girdle arthromyodysplasia.
Waardenburg Syndrome: Clinical Classification
Type 1 Dystopia canthorum Type 2 No dystopia canthorum Klein-Waardenburg syndrome (type 3) Type 1 and upper limb abnormalities Waardenburg-Shah syndrome (type 4) Type 2 and Hirschsprung disease
It seems that Karl May had described in Juggle-Fred the K-WS type 3. It was the abnormality of the upper-limb girdle, which was disfiguring Juggle-Fred's body, not a hump: "His body was … not of a short torso, narrow chest and long arms, as it seems to be the case with most humpbacks."
A hump is the result in most cases of kyphoscoliosis, i.e. lateral curvature of the spine with vertebral rotation, associated with an anteroposterior hump in the spinal column. This makes the torso short, resulting in small stature and a typical presentation of a humpback person. However the description of Juggle-Fred by Karl May was "…if this man would not have the hump [?], his appearance would be of pleasing powerfulness, even perhaps impressive." Juggle-Fred did not have a short torso, was not of a small stature. He even might have looked impressive, which a humpback person does not in appearance.
Karl May must have seen somewhere a person looking like Juggle-Fred. It is unlikely he used only the reference from "Schacht und Hütte" about the school child with different colours of the eyes, for the character of Juggle-Fred.
Picture of a three-year-old girl with Heterochromia. Hearing aids are indicative of her deafness.
The diagnosis is Waardenburg syndrome (autosomal dominant inheritance). Broad nasal bridge is noticeable.
References Please click on the hyperlinked reference numbers to return to your place in the text.
 "Juggling Fred" or "Fred the Juggler" sounds better in English.
 Karl May's Gesammelte Werke, Band 34 "Ich", Karl-May-Verlag Bamberg 1968, p. 359. - See also: "Der Geist des Llano Estakado - 1888" - KMG Reprint der Zeitschrifttenfassung, Hamburg 1983, p.156.
 Karl May: "Der Sohn des Bärenjagers." Haffmans Verlag AG Zurich 1996, p. 421.
 In (3), p. 422.
 This sentence is left out in: Karl May: "Untern Geiern." Karl May's Gesammelte Werke, Band 35, Karl-May-Verlag Bamberg 1953, p. 331.'
 Bernhard Kosciuszko: "Helden des Westens. Vorschlage zu einer Interpretation." Sonderheft der KMG No.42/1983, p.33 ff.
 Stefan Schmidt: "Der Mann mit dem blauen Auge." M-KMG 98, 1993, 52.
 "Mines and Foundries"
 Reprint Hildesheim 1979, p.168.
 See under (3).
 See under (5).