BKOXCHIOLES 



241 



of the pulmonary air sacs. The elastic fibres, derived from the 

 elastic layer of the bronchioles, pass over to the alveolar walls in 

 which they form a delicate network. 



The terminal bronchioles are short branching tubules leading 

 to broader spaces, the alveolar ducts (infundibula of Schultze), 







6 



FIG. 203. FKOM A SECTION OF A CHILD'S LUKO. 



a, a smajl bronchus; i, bronchioles; c, bronchioles ending in terminal bronchioles, 

 infundibuli, etc. ; d, terminal bronchioles in transection, they have a more regular con- 

 tour and thicker wall than the alveoli ; e, pulmonary arteries ; /, a bronchial artery ; ^, a 

 bronchial vein ; A, interlobular fibrous septum. Hematein and eosin. Photo, x 62. 



which are surrounded by pulmonary alveoli or air saccules. Ac- 

 cording to W. S. Miller* the alveolar duct is divisible into a main 

 vestibular space and several secondary spaces, the atria, which are 



17 



* Arch. f. Anat, 1900. 



