274 NATURAL THEOLOGY. 



ing no relation or fitness to the element which 

 surrounds them, but both to another element in 

 another place. 



As part and parcel of the same plan ought to 

 be mentioned, in speaking of the lungs, the provi- 

 sionary contrivances of the foramen ovale and 

 ductus arteriosus. In the foetus pipes are laid for 

 the passage of the blood through the lungs ; but, 

 until the lungs be inflated by the inspiration of 

 air, that passage is impervious, or in a great de- 

 gree obstructed. What then is to be done? What 

 would an artist, what would a master, do upon 

 the occasion ? He would endeavour, most proba- 

 bly, to provide a temporary passage, which might 

 carry on the communication required, until the 

 other was open. Now this is the thing which is 

 actually done in the heart. Instead of the cir- 

 cuitous route through the lungs which the blood 

 afterwards takes before it get from one auricle of 

 the heart to the other, a portion of the blood 

 passes immediately from the right auricle to the 

 left, through a hole placed in the partition which 

 separates these cavities. This hole anatomists 

 call the foramen ovale. This is likewise another 

 cross cut, answering the same purpose, by what 

 is called the ductus arteriosus, lying between the 

 pulmonary artery and the aorta. But both expe- 

 dients are so strictly temporary, that after birth 

 the one passage is closed, and the tube which 

 forms the other shrivelled up into a ligament. If 

 this be not contrivance, what is ? 



