RESPIRATION. 227 



bodies of animals deoxidated the air after death, and often as 

 much as during life, before decomposition was perceptible. k He 

 says also, that torpid animals, whose respiration had entirely 

 ceased, also carbonated it. As the latter fact cannot be ascribed 

 to the separation of carbon in the lungs, nor to the mere chemical 

 changes of decomposition, it probably arises from the functions of 

 the skin. 



The delicate surface of the lungs, and, indeed, of the whole air- 

 passages, is a great source of absorption from without, as well as of 

 impressions from gaseous and imponderable substances. Many poi- 

 sons affect the system by its means. It is also a great organ of elimi- 

 nation. Camphor, phosphorus, ether, diluted alcohol, gases, and va- 

 rious odorous substances, when introduced into the system, escape 

 in a great measure by the lungs : whence they are perceived in the 

 breath, and, perhaps for some time, long after they have left 

 the stomach. Dr. G. Breschet and Dr. Milne Edwards, conceiv- 

 ing that in the dilatation of the lungs by inspiration, the enlarged 

 space would cause not only the air to rush in, but the exhalation 

 from the surface of the air-cells and pleura to increase and ex- 

 ceed that from other parts, have made several experiments which 

 prove this to be the case. On injecting a small quantity of oil of 

 turpentine into the crural vein, the breath instantly smelt strongly 

 of it, and the pleura on being cut open did the same ; while no 

 odour of it arose on exposing the peritonaeum. If a larger quan- 

 tity was employed, it impregnated every part. If, instead of na- 

 tural respiration, artificial was instituted, in which the air does 

 not enter the lungs by the formation of a vacuum on the expan- 

 sion of the chest, but is forced into them and itself expands the 

 chest, no more exhalation of odorous substances took place from 

 the lungs than from other parts; and, indeed, if a cupping-glass 

 was applied over another denuded part, the odorous substance 

 was given out there, while the lungs afforded no sign of it. 1 



" The perpetual change of elements occurring in respiration 

 after birth, we shall show to be very differently accomplished in 

 the foetus, viz. by means of the connection of the gravid uterus 

 with the placenta. 



" But, when the child is born and capable of volition, the 

 congestion of blood that takes place in the aorta, from the ob- 

 struction in the umbilical arteries ; the danger of suffocation from 



k MSm. sur la Respiration. See Dr. Bostock, 1. c. vol. ii. p. 184. sqq. 

 1 Rfcherches Exptrimentales sur f Exhalation Pulmonaire. Paris, 1826. 



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