172 ARTERIAL BLOOD ACTS BY ITS 



the generation of animal heat. The globules of 

 the blood, by means of the property they possess 

 of giving off the oxygen they have taken up in 

 the lungs, without losing their peculiar character, 

 determine generally the change of matter in the 

 body. 



The second quality of the blood, namely, the 

 property which it possesses of becoming part of an 

 organised tissue, and its consequent adaptation to 

 promote the formation and the growth of organs, as 

 well as to the reproduction or supply of waste in 

 the tissues, is owing, chiefly, to the presence of dis- 

 solved fibrine and albumen. These two chief con- 

 stituents, which serve for nutrition and reproduc- 

 tion of matter, in passing through the lungs are 

 saturated with oxygen, or, at all events, absorb so 

 much from the atmosphere as entirely to lose the 

 power of extracting oxygen from the other sub- 

 stances present in the blood. 



77. We know for certain that the globules of 

 the venous blood, when they come in contact with 

 air in the lungs, change their colour, and that this 

 change of colour is accompanied by an absorj^tion of 

 oxygen ; and that all those constituents of the blood, 

 which possess in any degree the power of combining 

 with oxygen, absorb it in the lungs, and become sa- 

 turated with it. Although in contact with these 

 other compounds, the globules, when arterialised, 

 retain their florid, red colour in the most minute 

 ramifications of the arteries ; and we observe them 



