24 GENERAL SCIENCE 



alternately apply and then remove pressure upon the lungs 

 through the walls of the chest. This* may be accomplished 

 by holding'the hands against the lower ribs and throwing the 



FIG. 10. Resuscitation of the drowned expiration in artificial breathing. 



PIG. ii. Resuscitation of the drowned inspiration in artificial breathing. 



weight of the body first forward and then backward with 

 about the same rhythm as in natural breathing. 



SUMMARY 



Ventilation seeks to secure an ample supply of oxygen for respiration, 

 and at the same time to prevent the air about a person from becoming 



