served, is an object of veneration, and is regarded with peculiar deference. If found in their houses, as it frequently is, it must be petted, cared for, tenderly fed, and propitiated, for it is an object of worship, and occupies a high place in the mythology of the Hindoos. Indeed, the worship of serpents seems to have been widely adopted, and figures more or less in a vast number of the religions of the world. It is often referred to in the Scriptures, and is a subject of elaborate discussion in the profoundly learned and interesting volume of Ferguson, on "Tree and Serpent Worship."
We mentioned the fact that in most species serpents have but one fully-developed lung. Into the cavity of this the trachea or windpipe terminates, and it has been stated that they "in a manner swallow air." What takes place in the process of breathing appears to be this. Unlike mammals, serpents have no diaphragm, but by a movement of the ribs the cavity of the body is enlarged, and, a pressure being thus removed, the lung inflates and expands by the air passing into it. Another and opposite movement of the ribs expels the air, whence it appears that their process of breathing is essentially the same as in mammals. Nor are their lungs in structure essentially different. The air sacs or cells communicate with the principal pulmonary tube, but a vastly smaller surface is exposed to the inhaled air, and aëration of the blood is consequently extremely imperfect and incomplete.
Fig. 9.
Small Viperine Snake (Tropidonotus Viperinus).
Serpents are without proper organs of voice, the vibrating membranes being absent. The passage of air into and out of the lungs, if hurried and rapid, produces a hissing noise, the only voice possible to them, but which we fear makes less interesting their somewhat unprepossessing features.
