90 THE HUMAN LUNGS. 



Mineral chemistry teaches the composition of mineral substances by 

 analysis and synthesis. It makes minerals by mixing together their 

 components under favorable conditions. In like manner vegetable 

 chemistry makes plants, and animal chemistry makes animals. Na«- 

 ture does this, and so far nature is the only vegetable and animal 

 chemist. But though we cannot produce in her laboratory scien- 

 tifically, but only blindly, we can observe her processes and learn the 

 results. For example, the mixture of sexes produces animals, and 

 in a certain sense plants also. The mixture of breeds varies these 

 substances, namely, animals, and creates new compounds or animal 

 varieties. The mixture of opinions produces ideas, and then we 

 have intellectual chemistry. The present is distilled out of the past 

 by the same law. Chemistry then is the mineral term. Raise it a 

 step into the vegetable, and in plants it becomes propagation ; into 

 the animal, and it becomes generation : and so forth. This of syn- 

 thetical or creative chemistry. The terms alter as the theatre 

 changes. But to run one term through all the stages, is to miss 

 the essence of all but the lowest. When science does this, it not 

 only finds " sermons in stones," but is petrified by their discourses. 

 Dwelling therefore briefly, and under physiological protest, upon 

 the oxygen and carbonic acid disengaged, or absorbed, during respi- 

 ration, we proceed to remark, that the whole of the venous blood of 

 the body, which is comparatively exhausted by its circulation, and 

 also the whole of the new chyle or realized essence of the food, passes 

 by the pulmonary artery to the networks of minute blood-vessels 

 in their air cells, and so through the lungs, and in those fine vessels 

 is counted out and thoroughly sifted, and its purification takes place. 

 Whatever disabled portions it contains, are there taken to pieces, 

 their broken elements thrown awa}^ and the sound reconstituted. 

 Whatever injuries the blood may have received from the passions 

 of the mind, which as we know have all power to bless or to hurt it, 

 are palliated by the removal of clouds of exhalations, as witness the 

 odor of the breath. When the fire of life burns dark and fuligi- 

 nous, the windpipe is as the chimney that relieves the body of its 

 noxious smoke. Moreover, whatever crudities or superfluities the 

 new chyle, or the milky produce of our food, may contain, are expelled 

 by the lungs through the same channel. In short, the lungs are the 



