Zjo O F I N F A N G Y. 



An infant, at birth, pafles from one element 

 into another. When it efcapes from the waters 

 which furrounded it in the womb of the mo- 

 ther, it is expofed to the air, and inftantly feels 

 the impreffions of that adive fluid. The air 

 a(£ts upon the olfactory nerves, and upon the 

 organs of refpiration. This adion produces a 

 fhock, a kind of fneezing, which expands the 

 cheft, and gives the air a free paiTage into the 

 lungs, the veficles of which it dilates. After 

 the air remains for fome time, it is heated and 

 rarified to a certain degree, and the llimulus or 

 fpring arifuig from the dilatation of the fibres 

 re-ad:s upon this rarified fluid, and expells it 

 from the lungs. We will not here attempt to 

 explain the caufes of the alternate motion of 

 refpiration, but fl^all confine ourfelves to its 

 effects. 



This fundion is eflentially neceflary to the 

 exiftence of man and of many other animals. If 

 refpiration ceafes, the animal mufl: perifli j when 

 once commenced, it never fl:ops till death; and, 

 after the foetus begins to refpire, it continues 

 this adion without interruption. It is probable, 

 however, that the foramen ovale of the heart 

 does not clofe immediately after birth, and, confe- 

 quently, that part of the blood muft pafs through 

 that aperture. The whole blood, therefore, en- 

 ters not, at firft, into the lungs; and a new-born 

 child may perhaps be deprived of air for a con- 

 fiderable time without fuffocation. This con- 



jedure 



