Aldrovandus shows 3 illustrations under the name of "monstrum bicorpum monocephalon." Bustorf speaks of a case in which the nates and lower extremities of one body proceeded out of the abdomen of the other, which was otherwise perfect. Reichel and Anderson mention a living parasitic monster, the inferior trunk of one body proceeding from the pectoral region of the other.
Pare says that there was a man in Paris in 1530, quite forty years of age, who carried about a parasite without a head, which hung pendant from his belly. This individual was exhibited and drew great crowds. Pare appends an illustration, which is, perhaps, one of the most familiar in all teratology. He also gives a portrait of a man who had a parasitic head proceeding from his epigastrium, and who was born in Germany the same year that peace was made with the Swiss by King Francis. This creature lived to manhood and both heads were utilized in alimentation.
Bartholinus details a history of an individual named Lazarus-Joannes Baptista Colloredo, born in Genoa in 1617, who exhibited himself all over Europe. From his epigastrium hung an imperfectly developed twin that had one thigh, hands, body, arms, and a well-formed head covered with hair, which in the normal position hung lowest. There were signs of independent existence in the parasite, movements of respiration, etc., but its eyes were closed, and, although saliva constantly dribbled from its open mouth, nothing was ever ingested. The genitals were imperfect and the arms ended in badly formed hands. Bartholinus examined this monster at twenty-two, and has given the best report, although while in Scotland in 1642 he was again examined, and accredited with being married and the father of several children who were fully and admirably developed. Moreau quotes a case of an infant similar in conformation to the foregoing monster, who was born in Switzerland in 1764, and whose supernumerary parts were amputated by means of a ligature.
Winslow reported before the Academie Royale des Sciences the history of a girl of twelve who died at the Hotel-Dieu in 1733.
She was of ordinary height and of fair conformation, with the exception that hanging from the left flank was the inferior half of another girl of diminutive proportions. The supernumerary body was immovable, and hung so heavily that it was said to be supported by the hands or by a sling. Urine and feces were evacuated at intervals from the parasite, and received into a diaper constantly worn for this purpose. Sensibility in the two was common, an impression applied to the parasite being felt by the girl. Winslow gives an interesting report of the dissection of this monster, and mentions that he had seen an Italian child of eight who had a small head proceeding from under the cartilage of the third left rib. Sensibility was common, pinching the ear of the parasitic head causing the child with the perfect head to cry. Each of the two heads received baptism, one being named John and the other Matthew. A curious question arose in the instance of the girl, as to whether the extreme unction should be administered to the acephalous fetus as well as to the child.
In 1742, during the Ambassadorship of the Marquis de l'Hopital at Naples, he saw in that city an aged man, well conformed, with the exception that, like the little girl of Winslow, he had the inferior extremities of a male child growing from his epigastric region. Haller and Meckel have also observed cases like this.
Bordat described before the Royal Institute of France, August, 1826, a Chinaman, twenty-one years of age, who had an acephalous fetus attached to the surface of his breast (possibly "A-ke").
Dickinson describes a wonderful child five years old, who, by an extraordinary freak of nature, was an amalgamation of two children. From the body of an otherwise perfectly formed child was a supernumerary head protruding from a broad base attached to the lower lumbar and sacral region. This cephalic mass was covered with hair about four or five inches long, and showed the rudiments of an eye, nose, mouth, and chin. This child was on exhibition when Dickinson saw it. Montare and Reyes were commissioned by the Academy of Medicine of Havana to examine and report on a monstrous girl of seven months, living in Cuba. The girl was healthy and well developed, and from the middle line of her body between the xiphoid cartilage and the umbilicus, attached by a soft pedicle, was an accessory individual, irregular, of ovoid shape, the smaller end, representing the head, being upward. The parasite measured a little over 1 foot in length, 9 inches about the head, and 7 3/4 inches around the neck. The cranial bones were distinctly felt, and the top of the head was covered by a circlet of hair. There were two rudimentary eyebrows; the left eye was represented by a minute perforation encircled with hair; the right eye was traced by one end of a mucous groove which ran down to another transverse groove representing the mouth; the right third of this latter groove showed a primitive tongue and a triangular tooth, which appeared at the fifth month. There was a soft, imperforate nose, and the elements of the vertebral column could be distinguished beneath the skin; there were no legs; apparently no vascular sounds;there was separate sensation, as the parasite could be pinched without attracting the perfect infant's notice. The mouth of the parasite constantly dribbled saliva, but showed no indication of receiving aliment.