160 



RESPIRATION. 



smaller, and their networks of capillaries are closer than 

 those nearer to the circumference, in adaptation to the more 



FIG. 



Air-cells of lung, magnified 350 diameters, a, epithelial lining of the cells; 6, 

 fibres of elastic tissue ; c, delicate membrane of which the cell-wall is constructed 

 with elastic fibres attached to it (after Kolliker). 



FIG. 61. 



Capillary network of the pulmonary bloodvessels in the human lung (from 

 Kolliker) \. 



