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V. Description of an extraordinary Human Foetus. In a Letter 
from Mr. Benj. Gibson, Surgeon , to H. Leigh Thomas, Esq . 
F.R.S . 
Read February 8, 1810. 
Manchester, June, 1S09- 
Dear Sir, 
I have lately had an opportunity of inspecting a singular 
human foetus, at the full period of utero-gestation, and hope 
that a history of it will not be unacceptable to the learned 
Society, of which you are a member. Some deviations, which 
it exhibits, from the usual form and structure of the human 
body, have not (as far as my information extends) been yet 
recorded ; and the consideration that they were all apparently 
compatible with life, gives additional interest to the subject ; 
for if the difficulty of parturition had not proved almost im- 
mediately fatal, the complex structure of the animal would 
have formed no impediment to its existence. 
Instances of two entire human bodies united together, are 
by no means rare in the collections of anatomists. Sometimes 
their conjunction takes place back to back ; sometimes the 
reverse ; at other times side by side ; or in such a position as 
to form a kind of cross: the two heads lying in one direction, 
and the opposite extremities in another, and intersecting it at 
right angles. 
That species of monstrosity, however, in which two bodies 
are merely united together, does not display in a striking 
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