2-30 Professor Clark on a Case 



hearts, enclosed in their proper pericardia, with their veins and 

 arteries. In the Petersburgh case, the circulation entirely differed 

 from ours, but yet was single for the whole mass. There were two 

 hearts, one much more perfect than the other: which supplied the 

 greatest number of arteries, as the two aortae, and received the 

 greatest number of veins. The imperfect heart, after supplying 

 a portion of the arteries of the head and lungs, and receiving some 

 of the veins, anastomosed by its descending aorta, with the prin- 

 cipal vessel of the other heart, and by a large venous trunk with the 

 descending cava of the same. This case of Duvernoy, as far as 

 the circulation is concerned, approximates to one lately described 

 by Barkow, Chap. 11. No. 6059 of the Berlin Museum: two males, 

 with the brains nearly distinct. I know indeed of no recorded in- 

 stance of a human monster with a circulation nearly similar to 

 that which I have described. But I suspect the Turin monster 

 to have been such. The circulation in a double pig, described 

 by Haller, Op. JVJin. Vol. in. Sect. 16, very nearly resembles it. 

 And that by Antomarchi in a double sheep, Ann. des Sc. Nat. 

 Tom. xiv. is also nearly similar. 



It has long - been a question, whether double monsters arise 

 from a single germ, or from two germs accidentally united. But 

 the question ought to be much restricted before an answer can be 

 given to it. Every appearance is monstrous which is unusual : and 

 causes may exist capable of producing, in the uterus, an unnatural 

 union of twins, more or less complete in appearance and yet not 

 involving essential parts: capable therefore of producing a double 

 monster. Such slight connexions as that of the Siamese youths 

 may be conceived to have been thus produced, without doing 

 much violence to the imagination. But to suppose that pressure 

 so forcible should have been applied to twin germs, as to melt 



