ARISTOTLE. 37 



than three chambers has always been considered as a 

 very gross blunder on the part of Aristotle. Even 

 Cuvier, who generally lavishes upon the philosopher 

 the most extravagant praise, sneers at this. Professor 

 Huxley, 1 however, has shown, by a comparison of 

 several passages from the " History of Animals," that 

 what we now call the right auricle was regarded by the 

 author as a venous sinus, as being a part not of the heart, 

 but of the great vein (i.e. the superior and the inferior 

 vena cava). 



Aristotle speaks of the lung as a single organ, sub- 

 divided, but having a common outlet the trachea. 

 Elsewhere 2 he says, " Canals from the heart pass to the 

 lung and divide in the same fashion as the windpipe 

 does, closely accompanying those from the windpipe 

 through the whole lung." His theory of respiration, as 

 explained in his treatise on the subject, is that it tempers 

 the excessive heat produced in the heart. The lung is 

 compared to a pair of bellows. When the lung is ex- 

 panded, air rushes in; when^it is contracted, the air is 

 expelled. The heat from the heart causes the lung to 

 expand cold air rushes in, the heat is reduced, the lung 

 collapses, and the air is expelled. The cold air drawn 

 into the lung reaches the bronchial tubes, and as the 

 vessels containing hot blood run alongside these tubes, 



1 " On some of the errors attributed to Aristotle." 



2 " History of Animals," i. 17. 



