[Form of branching of pulmonary air pathways in the canine lung]

The degree of regularity in bronchial dichotomy has been studied in 5 corrosive preparations of the dog bronchial tree by the method of E. R. Weibel. It has been demonstrated that a high degree of regularity is specific for the dog lungs that makes 0.82 +/- 0.12 regarding small and large diameters. Approximation in distribution of bronchi having the diameter of 3--3.5 mm in 1--9 generations by means of binomial distribution gives a good result. The greatest bronchial rate with the diameter mentioned above has been registered in 5--7 generations. Theoretical data are presented to demonstrate the necessity in regularity of bronchial branching in order to maintain an optimal gaseous exchange in lungs.