1 34 HUMAN LONGEVITY. 



production and maintenance of this power impairs longevity, 

 not less than its too lavish expenditure in the various abuses 

 and vices of social life. 



Hence the vast importance of all that may be done by 

 open air, exercise, ventilation of dwellings, and removal of 

 noxious exhalations, on behalf of this great function of life. 

 These things are better understood than they were, and more 

 is attempted and effected for their attainment. Medical 

 science is now called upon to prevent disease, as well as to 

 restore health. Much more might be accomplished in this 

 way, as well for individuals as for communities, were the 

 healthy state of respiration cultivated with the same care 

 which is given to the actions of the stomach and alimentary 

 organs. We doubt not, for instance, that this function is 

 capable of being restored, improved, and maintained in effi- 

 ciency, by well-ordered exercises of the lungs ; and by due 

 attention to the mechanism of these organs in all that belongs 

 to the habits of life. It may not occur to our readers, and 

 yet it is strictly true, that the familiar conditions of posture 

 of body, speaking, singing, &c., are deeply concerned in this 

 matter ; the more so from the very familiarity of every-day 

 use. If forty cubic inches of air taken into the lungs at each 

 inspiration are required for the purposes of their function, 

 and thirty or twenty only are inspired, it is certain that the 

 blood will not be duly changed, and that every organ and 

 action of the body will suffer more or less by this defi- 

 ciency. To enlarge the quantity then in such cases is an 

 object of high importance ; not sufficiently regarded, we may 

 add, in the medical practice of our day. 



Of the value to health of the purity of the air we breathe, 

 it is hardly necessary to speak. Free ventilation is here the 

 main agent in our hands, whether we look to the replacement 

 of air despoiled of its oxygen, or to the removal of noxious 

 matters present in it. Our actual knowledge, it must be 



