HUMAN MALE MONSTER. 227 



We therefore muft conclude, that the circulation of the 

 blood in the placenta and body of the monfter, was carried on 

 by a well regulated mufcular action of the blood-veffels. In 

 one of the worms, the echinus efculentus, I found in the me- 

 fentery, which is a principal part of it, two fuch large vefTels 

 without a heart, and which, we can fcarcely doubt, refembled 

 our aorta and cava, and circulated its fluid ; and in fifties *, 

 the blood which pafTes through the liver defcribes three circles, 

 and in all other parts of the fi(h the blood defcribes two circles 

 before it returns to the heart ; which motion of it we muft 

 fuppofe to be chiefly owing to the mufcular action of the 

 vefTels, as the force of the heart appears to be as much fpent 

 in the gills of the fifli as in the lungs of a man. 



From confidering the manner and caufe of the motion of the 

 blood in this monfter, and comparing with it the motion of 

 the blood in fifhes and in the fea egg, we are, by analogy, led to 

 the following general conclufions : 



1. The arteries contribute much to the circulation of the 

 blood in our bodies. 



2. It is probable that, in man, the veins Iikewife aflift: in cir- 

 culation ; and, in particular, there can be no doubt, that the 

 vena portarum, by its action, contributes much to the motion 

 of the blood through our liver. 



3. For the like reafons, we may conclude, that arterious 

 vefTels, independent of the impulfe of the heart, may act in 

 fuch a manner, as to perform the fecretion of liquors, to nourilh 

 the folids, and to add to their bulk; and particularly, that the 

 branches of the vena portarum change certain parts of the 

 blood into bile. 



F f 2 Remarks- 



* See Monro on Fifties, p. 6jr. Taj. xliii. 



