SMITHSONIAN CONTRIBUTIONS TO KNOWLEDGE. 



989 



THE 



Composition of expired Air 



AND ITS 

 EFFECTS UPON ANIMAL LIFE. 



BY 



J. S. BILLINGS, M.D., S. WEIR MITCHELL. M.D. 

 AND D. H. BERGEY, M.D. 



CITY OF WASHINGTON : 

 PUBLISHED BY THE SMITHSONIAN INSTITUTION. 



1895. 



