Thorax organs. Coloured historical engraving of the organs in the human thorax. This illustration is taken from La vie physiologie humaine" by Gustav Le Bon, published in Paris in 1874. It shows the respiratory system and other organs. The lungs (green) are protected by the rib cage, and lie either side of the heart (pink). The engraving shows the trachea (brown) in the neck supplying air to the lungs. The thyroid gland (pink, "W"-shaped) is seen resting against the trachea. Also visible (in the abdomen) are the liver (dark brown) and the stomach (orange). The carotid arteries (red) and jugular veins (blue) are seen running to and from the head."