3G4 PERVIOUS FORAMEN OVALE CYANOSIS. 



observation of this description in the lower animals. Dr 

 Wardrop says, in his learned work, On the Diseases of the 

 Heart: " The membrane which covers the foramen ovale 

 is sometimes as thin as a spider's web, or it resembles a piece 

 of lace. At other times it is found re-opened in such a man- 

 ner as to permit an intermixture of the venous and arterial 

 blood. This condition of the foramen ovale was first described 

 by Abernethy, but little notice has been taken of it by sub- 

 sequent pathologists, though its accuracy is corroborated by 

 morbid preparations in every museum. ( Having formerly 

 been much surprised to find the heart so little affected when 

 the lungs were greatly diseased, and observing in one or two 

 instances, that the foramen ovale was open, I was led to pay 

 more particular attention to the state of that part, and I have 

 found this to be almost a constant occurrence in those sub- 

 jects where pulmonary consumption had for some time existed 

 previous to the person's decease. I took notice of this circum- 

 stance thirteen times in the course of one year, and, in seve- 

 ral instances, the aperture was sufficiently large to admit of 

 a finger being passed through it. Now, as the septum auri- 

 culum is almost constantly perfect in subjects whose lungs 

 are healthy, I cannot but conclude that the renewal of the 

 foramen ovale is the effect of disease nor will the opinion 

 appear, on reflection, improbable; for the opening becomes 

 closed by the membranous fold growing from one edge of it 

 till it overlaps the other; and their smooth surfaces being 

 kept in close contact by the pressure of the blood in the left 

 auricle, they grow gradually together. But should there be a 

 deficiency of blood in the left auricle, and a redundance in 

 the right, the pressure of the latter on this membranous parti- 

 tion will so stretch and irritate the uniting medium as to 

 occasion its removal, and thus a renewal of the communica- 

 tion between the auricles will take place/ " 



