ABNORMAL RESPIRATION l6l 



cu. ft. will be necessary for inspiration during twenty-four hours. 

 This amount represents some 300 cu. ft. of atmospheric air 

 which an ordinary person must have in that time. 



But this estimate allows nothing for increased respiratory ac- 

 tivity, which inevitably occurs from some of the numerous con- 

 ditions influencing it. It is found that in prisons and other in- 

 stitutions of confinement it is not safe to allow each person less 

 than 1,000 cu. ft. of atmospheric air. In crowded houses, where 

 this space per individual cannot be obtained, it is necessary, in 

 order to avoid unpleasant results, to change the air continuou'sly, 

 or at frequent intervals, Natural and artificial means are em- 

 ployed to accomplish this end. 



Respiration of Various Gases. The inhalation of pure 

 oxygen is not deleterious unless it be under higher tension than 

 in atmospheric air, when it becomes a local irritant. The blood 

 will not, however, appropriate more than the usual amount. 

 Nitrous oxide will sustain respiration for a time, but soon pro- 

 duces unconsciousness and asphyxia, probably because it unites 

 so firmly with the hemoglobin of the corpuscles. Hydrogen may 

 be inhaled with impunity if it contain also oxygen in the atmos- 

 pheric proportion. Carbon monoxide is poisonous because it 

 unites with hemoglobin to the exclusion of oxygen and will not 

 dissociate itself. Sulphurreted, phosphoretted and arseniuretted 

 hydrogen are destructive of hemoglobin and consequently poison- 

 ous. Pure carbon dioxide cannot be inhaled for any length of time. 



Abnormal Respiration. The term eupnea is used to describe 

 normal, tranquil breathing. Apnea is suspended respiration. 

 Hyperpnea is exaggerated respiration. Dyspnea is labored 

 breathing. Asphyxia is essentially a want of O characterized 

 by convulsive respirations, and later by irregular shallow breath- 

 ing. The last two named deserve some attention. 



Dyspnea may be due to either a deficiency of O or an excess 

 of CO 2 in the blood. When an animal is made to breath in a 

 small, confined space the amount of O soon becomes insufficient, 

 ii 



