In a previous paper1 reporting the results of a capillaroscopic study of the pulmonary alveolus in the living dog, the capillary blood supply was merely mentioned. In this subsequent report, it is our purpose to describe the capillary circulation in detail.
METHODS AND RESULTS
It was stated in the previous report that the normal pleura may be regarded as a glass window through which one can study the structure and activity of the alveolus and its capillaries without disturbing the normal activity of these tissues.Our observations were made by means of a Zeiss capillary microscope which was devised by Otfried Muller.2 This microscope has a magnification of 60 and has a 6 volt lamp inside the tube of the microscope. The advantage of this instrument over others is that the light is direct and as the focus is moved the light moves with it so that the degree of