232 THE HOUSE I LIVE IN. 



the right auricle and ventricle of the heart, its 

 properties become greatly changed. It is now 

 of a deep purple hue, and - has hence often 

 been called black blood. 



In this state, it is found to be loaded with 

 too great a proportion of carbon ; and this, too, 

 notwithstanding what has been done by the 

 skin ; for it is a most striking fact, that this 

 very work of purifying the blood, of which 

 I am about to speak as taking place in the 

 lungs, takes place in a small degree all over 

 the surface of the body. Still it does not com- 

 plete the work, and the blood still comes from 

 the heart through the pulmonary artery to the 

 lungs in its impure, purple or black state not 

 only overloaded with carbon, but mixed with 

 such other noxious ingredients as render it 

 unfit for the use of the organs where it travels, 

 in forming their various parts, secretions, &c. 

 It also brings back with it at least a few 

 hours after every meal a mass of chyle just 

 mixed with the blood, which probably needs a 

 change in the lungs, before it is fit to become 

 blood, and afford nourishment to the system. 



Arrived in the lungs, it is spread, almost 

 immediately, over the vast space which is af- 



