the result (as other organic colouring matters possess the property of 

 absorbing oxygen and giving off carbonic acid gas), he took a small 

 quantity of pure blood-hsematin prepared by Verdeil's process, and 

 put it into a vessel along with 1000 volumes of ordinary air. After 

 the air had been kept in contact with the heematin for some months, 

 the gas was analysed and found to contain 



Oxygen 16'01 



Carbonic acid 3'80 



Nitrogen 80-19 



100-00 



The pure colouring principle of the blood, therefore, by exposure to 

 ordinary air, gives off carbonic acid gas, and becomes oxidized in two 

 ways ; first by a loss of carbon, and secondly by direct combination 

 with oxygen. The author considers that this last result furnishes 

 additional evidence of the correctness of an opinion he hazarded two 

 years ago*, imputing to the colouring matters of the vegetable and 

 animal economy a more important office in the function of respiration 

 than they before had been considered to possess, and regarding 

 their principal function in organized beings as the absorbing of 

 oxygen and exhaling of carbonic acid a view altogether irrespective 

 of Liebig's well-known hypothesis, which assigns the above office to 

 the iron of the blood-hsematin. 



The author concludes by expressing the hope that his experi- 

 ments will be considered as at least serving to establish one import- 

 ant fact respecting which further evidence was wanted, namely, that 

 the entire volume of the respired oxygen is not transmitted in an 

 uncombined state (as Magnus believes) to the various organs and 

 tissues of the body, but that a portion of it enters into chemical com- 

 bination with some of the organic constituents of the blood. 



* Verhand. Physik-Medizin. Gesellsch. zu Wiirzburg, Bd. v. 1854 ; and Erd- 

 mann's Journ. f. prakt. Chemie, Bd. Ixiv. H. 5. 1855. 



