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VI. An examination into the structure of the cells of the human 
lungs ; with a view to ascertain the office they perform in res- 
piration. By Sir Everard Home, Bart. V. P. R. S. Illus- 
trated by microscopical drawings from the pencil ofF. Bauer, 
Esq. F. R. S. 
Read February 8, 1827. 
N o subject connected with physiological enquiry has more 
excited the attention of the anatomist and chemist, than 
respiration ; but the association between this subject and 
animal heat, which has so long been supposed to exist, has 
led to the belief, for the last century, that both enquiries 
belong more particularly to chemistry than anatomy, and I 
may probably be considered as going out of my province in 
taking up this investigation. On the other hand, I see reason 
to believe that the process of respiration is in itself more 
simple than is imagined, and more within the reach of disco- 
very by means of accurate anatomical knowledge of the parts 
employed, than by means of acquaintance with the intricacies 
belonging to chemical affinities : I carry this so far as to 
contend that no explanation of respiration upon chemical 
principles is to be depended on, unless it accord in all respects 
with the anatomy and physiology of the lungs , by which the 
assumed process takes place. 
The present theory respecting respiration adopted by the 
chemists, is, that this process decarbonises the blood in the 
following manner ; at every inspiration a . compound of 
