Abstract :With the help of new devices and methods an attempt was made to study circulation in the lungs
between the alveoli and in the very alveoli on the lungs in an almost intact thorax of white rats.
Alveoli were shown to receive the blood from a dense network of microvessels 20-50 µm in diameter
contrary to previous concepts about single thin microvessels supplying each alveolus. Efficient
oxygenation of the blood was shown to be attained by spreading the blood in a thin layer over the
whole surface of the inner coating of an alveolus and by rotation of this layer in the alveolus.