upon Animal Bodies. 7 



into the bosom of the atmosphere, what are the effects 

 produced by this sudden change in the mode of exist- 

 ence, in passing from the matrix into the air ? Inspi- 

 ration is ordinarily and chiefly performed by the action 

 of the intercostal muscles and diaphragm ; the ribs and 

 sternum are elevated and pushed forwards by the con- 

 traction of the intercostal muscles, which, joined to the 

 contraction of the diaphragm, dilates the thorax in even- 

 direction. 



Thus the lungs, which come in contact with the ribs 

 and diaphragm, and passively obey their motions, re* 

 main quiescent, whilst a cavity is produced, into which 

 the air is forced by its undequaque pressure to preserve 

 its equilibrium. 



This action is involuntary. The infant does not in- 

 spire from an instinctive principle, or any supposed ap- 

 petite. The air alone, by its stimulus, like light on 

 the iris, excites the living powers of the proper organ, 

 by which alone the life of the animal can now be main- 

 tained, viz., the muscles which enlarge the chest, and on 

 whose immediate action depends the continuance of life. 



Hence, in cases of still-born infants, stimuli far more 

 powerful than is the air, are requisite to excite this orga- 

 nic action. An ingenious physician related to me a case 

 of restoration of a still-born infant by moderate and con- 

 tinued flagellation, when the ordinary stimuli had been in 

 vain attempted, which induced him to remark to the 

 bye-standers, who thought it a cruel operation, that he 

 presumed it was the first time they had ever known of 



