EXPLANATION OF THE PLATES. 



PLATE XLIX. 



Fig. 1. A portion of the pleural surface of the human lung, 

 with the vessels of the second order injected. 

 Magnified 100 diameters. 



Fig. 2. A section of the human lung, showing the natural 

 appearance and form of the air cells as seen with- 

 out injection, also exhibiting numerous particles 

 of the conoidal ciliated epithelium which lines 

 them. 



Fig. 3. Capillaries of the human lung. Magnified 100 dia- 

 meters. The drawing was made from a very beau- 

 tiful preparation injected by Mr. Quekett. 



