Kach figure represents a square millimeter of a section of lung 
The figures were traced at the same 
magnification (X 100) and reduced in reproduction to X 60. The double lines 
represent blood vessels. Fig. 5, section of a child’s lung. Fig. 6, section of an 
opossum lung. Tig. 7, section of an adult human lung. 
284 
Figs. 5 to 7 
tissue, traced with a projection apparatus. 
