Plate II.
THE LUNGS
R.Right Lung.L.Left Lung.
W.Windpipe (Trachea).
V.Voicebox (Larnyx).

The top part of the left Lung is represented as partly cut away in order to show the ramifications of the Bronchial Tubes.

Plate III.

THE CHEST.

The Lungs are enclosed in the chest, which they fit exactly, and of which they occupy by far the largest portion, leaving but a small space for the heart. They consist of two halves ([pl. II], R, L), each roughly resembling the upper part of a sugar-loaf somewhat flattened and hollowed out at the bottom. The left shows two and the right three distinct flaps or lobes. They are only connected by means of the windpipe ([pl. II], W) and its branches.

The Chest ([pl. III]) is an air-tight chamber, which is narrower above than below. It is formed by the spine at the back, twelve ribs ([pl. III], 1 to 11, the twelfth not visible on the drawing), with their inner and outer muscles on either side, the breast-bone ([pl. III], B B) in front, the root of the neck at the top, and the midriff or diaphragm ([pl. I], M) at the bottom.