MONSTER. 
cations of a head compofed of two joined together, to 
two bodies, apparently perfeCl in all their parts, adhering 
at forhe point to each other. We might form a 1 'eries, 
having at one end a body naturally formed, and at the 
other two natural bodies joined, in which the interme¬ 
diate gradations fhould be filled by individuals differing 
almoft imperceptibly from each other. Part of fuch a fe- 
ries, in that kind of monftroflty in which there is a double 
head, is exhibited in the work of Soemmerring, (Abbil- 
dung, See. Mentz, 1791.) tab. 2. to 7. 
In all thefe fpecimens, the parts placed at the point of 
union are the raoft worthy of notice; they are not like the 
organs of a natural body, but exhibit unions of the parts 
c>f two bodies, in various degrees and fhapes. If it were 
poffible for two heads, from each of which one-third or 
one-fourth had been cut away, to be joined and grow to¬ 
gether by the cut furfaces, we fhould have the appear¬ 
ances exhibited in thefe cafes. In the fame way, two 
tracheas or oefophagi, coming from the two halves of 
a double head, are united below into one tube, or the 
finall or large inteftines from two diftinCt upper portions 
of a body are joined into one canal, or the blood-velfels 
united in the fame way, or the fkeletons joined in various 
manners; or, on the contrary, the organs may be fimple 
above, and bifurcated downwards, to produce double 
parts for double bodies. In all fuch inftances, organs are 
formed, for which there is no model in the common ftruc- 
ture; the points of bifurcation, or divifion of the various 
canals mentioned above, are like nothing in the naturally- 
formed body. 
The flighted: deviation from the common ftru&ure in 
this direction is exhibited in Soemmerring’s fecond plate. 
The head is very broad ; there are only two eyes, placed 
far apart: and the nofe and upper lip are divided by a 
confiderable fifl'ure. On each fide of this fiffure there are 
about two-thirds of a nofe. The third plate reprefents a 
head of fuch fize and form as would refult from joining 
two two-third heads. The halves of this double head are 
fymmetrical, and refemble each other in all refpe&s ; the 
features are exactly alike, and each upper lip has a cleft 
in it. In the following inftances the fame clofe refem- 
blance of the features is obferved, and in one there is a 
hare-lip on both fides, yet the right is rather larger and 
better formed than the left fide;. and the fame circum- 
ftance is noticed in the other inftances reprefented by 
this author j and he conceives that it admits of explana¬ 
tion by the circumftance of the right half being nearer to 
the heart. In the middle of this broad head, of which 
each lateral divifion contains its eye, nofe, and mouth, 
there is a large unnaturally-formed eye. Each lid is ma- 
nifeftly compoled of.two, united by their outer extremi¬ 
ties, inftead of joining correfponding extremities of the 
lower lids to form external angles; the oppoiite ends of 
thefe lids are joined, and form two angles turned towards 
the noles of the two halves of the head. The globe, 
obferved externally, feems compofed of two two-thirds 
united together; two optic nerves enter it behind, and 
the number of mufcles exceeds that of a lingle eye. There 
were two lenfes, two choroid coats, and irifes. A fliarp 
projeCling edge of the fclerotica, correfponding to an ex¬ 
ternal depreftion, formed the back of a feptum dividing 
the interior of the globe; the two choroids, lying in con- 
rail, continued this partition, but it did not reach to the 
cornea. The two iriles were united, and formed one large 
n il; a pointed projection in the middle of the upper 
lower edge of this, as well as its breadth, lhovved that 
it was made of two joined together. Under this large 
eye, there was a broad furface compoled of the two cheeks 
and chins united; a depreflion Ihovved the diyifion of the 
right and left cheeks. The refophagi and tracheae of the 
two halves joined at the bottom of the neck. In the 
foetus, reprefented in the fifth plate, the face is compofed 
of two three-quarter faces. I here are four well-formed 
eyes; the outer angles of the two middle eyes exhibit the 
ordinary appearance, but are united in the middle of the 
yp,!.. XV. Np. 1077. 
701 
head. The fixth plate exhibits a ftill nearer approach to 
two heads. The two inner eyes are apart from each 
other; a depreftion above marks the diftinClion of the two 
heads, and the bottom of this is filled by an irregularly- 
formed external ear, appearing as if it had been made by 
blending the oppofed ears of the two heads. In the pre¬ 
ceding inftances there had been only two ears; here there 
were three, two of the ordinary ftruClure and a third com¬ 
pound one. A ftill more complete divifion of the head 
into two lateral heads is (hown in the feventh plate. 
There are in this four ears, and the two middle ones are 
in contact at their convex furfaces. From this part x 
deep depreftion runs to the breaft, marking the diftinCtion 
of the cheeks and chins. 
The cafes in which the head is fingle, but compofed of 
two imperfeCt heads united, are followed by others, in 
which there are two completely diftinCt heads, joined 
higher or lower in the neck. See MoAro on the Nervous 
Syltem, tab. 8. 
In the next fet of cafes, the double parts of the body 
are continued farther down than in the preceding 
clafs. There are two heads and necks and two arms ; tin; 
double parts join in the chell, and the body is lingle be¬ 
low. See Hilt, de l’Acad. des Sciences, 1745, P- 2 9- 
Sometimes the union takes place lower down in the; 
cheft, or in the abdomen or pelvis; there are then three 
or four arms in fuch cafes, and two lower limbs. In x 
feetus deferibed by Duverney, Com. Acad. Petropol. iih 
188. there were two imperfeCt arms between the twq 
necks. The two inner rows of ribs joined together, and 
did not run on to the fternum ; there were three cavities 
in the thorax, a right and a left proper, and a middle 
common one, and two hearts. In another there were twq 
perfect lateral upper extremities, and a middle imperfeCt 
one; a double fpine as far as the loins; two hearts, and 
aorta:, which united below the diaphragm. (Phil. Tranf. 
N° 138.) In one examined by Lemery, there were two 
vertebral columns, and tracheae, double lungs, a lingle 
heart compofed of one auricle and ventricle, two aortas 
joined in the back, two ftomachs and duodena, which 
united into one inteftine. (Mem. de l’Acad. des Sciences, 
1724, p. 63.) In another the vertebrae were joined in the 
back ; there were two cefophagules and one ftomach, a 
double heart, and large velfels united in the loins. (Haller, 
Opera Minora, p. 85.) A child with two heads and chefts, 
and four upper limbs; one pelvis and penis, and two lower 
limbs, is deferibed in the Journal des Savans, 1684, p. 27. 
For an account of a much greater number of thefe cafes, 
and numerous references, fee Haller De Monjiris, lib. i. 
Through the preceding dalles there is a gradual, ap¬ 
proach, from the fingle body to the union of two, in other 
refpeCts, perfeCt bodies. The moll complete dilfe&ion of 
a double child is furnilhed by Haller. The mother had 
brought forth three well-formed children, and carried 
this double production the full time. It conlifted of two 
well-formed girls, of the ordinary fize, with abundant 
hair, perfeCt nails, and rather elegant features. The chefts 
and epigaltria were united, the two bodies being free in 
every other part. The labour was very difficult and te¬ 
dious, and attended with the death of thefe children, 
which, but for this reafon, might probably have lurvived, 
their organization leemed fo perfeCt in all relpeCts. The 
umbilical chord contained lour arteries and oqe vein ; 
the abdomen was lingle above the navel, and double be¬ 
low ; it contained one liver, to which there were attached, 
two gall-bladders. The greater diaphragm was Ample, 
and terminated below in double appendices for the twa 
bodies. A large fingle heart was placed in the middle of 
the cheft; but all the. blood-velfels were double. The 
pulmonary veins of one body opened into the iuperior 
cava, while in the other there were two fuperior cava:, and 
the pulmonary veins had diftinCt openings in the heart, 
The latter organ conlifted of one auricle, receiving the 
terminations of all the veins, and of two ventricles, from 
each of which an aorta and a pulmonary artery arofe. All 
8 Q 
