. Reptiles and birds : a popular account of their various orders : with a description of the habits and economy of the most interesting . Birds; Reptiles. 182 INTEODUCTOBT The position renders a double sj^stem of breathing necessary. Vital heat in animals is always in proportion to their respiration, for the oxygen of the air, which penetrates every cell and cavity of their bones, feathers, and body, warming and giving increased activity to their circulation, and specific lightness to their bodies, from its rich organisation enables birds to live in the coldest atmo- spheric regions.
. Reptiles and birds : a popular account of their various orders : with a description of the habits and economy of the most interesting . Birds; Reptiles. 182 INTEODUCTOBT The position renders a double sj^stem of breathing necessary. Vital heat in animals is always in proportion to their respiration, for the oxygen of the air, which penetrates every cell and cavity of their bones, feathers, and body, warming and giving increased activity to their circulation, and specific lightness to their bodies, from its rich organisation enables birds to live in the coldest atmo- spheric regions. In Fig. 46 the respiratory organs of a Pigeon are represented. The trachea, or wind- pipe, is composed of many bony rings, varying in diiferent species. In the Falcons it is slightly , and tapers in a small degree ; but in many genera it presents dilatations and contractions, and in others it is vari- ously curved, two slender muscles, which run along its sides towards the sternum, serving to contract it. In many of the song-birds several pairs of small muscles are attached to the lower larynx where the tube bifurcates, by which they are enabled to control this organ, which is the producer of their note. The trachea carries the air to the lungs in a Pigeon, and sepa- Fig Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Figuier, Louis, 1819-1894; Gillmore, Parker. New York : D. Appleton
Size: 1351px × 1850px
Photo credit: © The Book Worm / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1800, bookdecade1870, booksubjectbirds, booksubjectrep
