Morphology of the bronchial tree in the dog.

Polyester resin casts were made of the bronchial trees from three adult dogs. The branches were ordered by the method of Strahler and the number of branches in each order counted. The length and diameter of each branch was measured and the mean dimensions of branches in each order calculated. When number, mean diameter and mean length of branches in each order are plotted semilogarithmically against order, linear relationships are found. From the data thus obtained a dimensional model of the dog's bronchial tree has been developed.