[ 3*6 3 
XIII. A Description of a very unusual Formation of the human 
Heart. By Mr. James Wilson, Surgeon. Communicated by 
Matthew Baillie, M. D. F. R. S. 
Read May 3, 179S. 
The heart is an organ of so much importance in the animal 
ceconomy, and is so immediately concerned in the support of 
life, that any unusual deviation from its natural form and situa- 
tion in the human body, has always been considered as a subject 
of some interest by the physiologist; such deviations have, 
therefore, not unfrequently been submitted to the consideration 
of this and other learned Societies. Many circumstances re- 
specting the circulation of the blood, and respiration, wholly 
unknown to our ancestors, have lately been ascertained; but 
we are not as yet arrived at a perfect knowledge of these im- 
portant actions. Difficulties yet remain; more information may 
still be acquired ; and the reasoning upon these subjects will 
be less liable to fallacy, in proportion to the number of facts 
which have been observed, and the accuracy of the observa- 
tions. These are the reasons which have induced me to lay 
before this Society, a description of a monstrosity in the human 
heart, very singular in its nature, and which, I believe, has 
not hitherto been observed or described. I have consulted the 
works of those authors who were the most likely to have 
