COMPOSITION OF THE BLOOD 



387 





Their red color is due to an iron-protein combination called haemo- 

 globin. Haemoglobin will combine chemically with oxygen, 

 forming a bright red 

 compound called 

 oxy haemoglobin. In 

 the parts of the 

 body where oxida- 

 tion is going on, the 

 haemoglobin gives 

 up its oxygen sup- 

 ply. At the same 

 time the plasma 



takes up the carbon dioxide which is given off by the cells. The 

 result of this interchange of gases causes a change in the color 

 of the blood from a dull to a bright red. 



The colorless corpuscles, of which several kinds are found in the 

 blood, are irregular in outline, as they constantly change their 



form. The color- 



-kS/hite Corpuscle 

 L.recC corpus-cle. 



Are the red corpuscles cells ? Explain. 



:■• 



germs 



cdtevle&s cor-jnc^de-r 



&Ls\ % 'x 



When germs or any foreign organisms enter the body, the 

 colorless corpuscles, phagocytes, accumulate and either ingest 

 the germs directly or with the aid of certain substances, opsonins, 

 destroy them. 



less corpuscles are 

 less numerous than 

 the red, the ratio 

 being about 1 to 

 700 in a normal 

 person. They in- 

 crease in number 

 during certain dis- 

 eases. They have 

 the power of move- 

 ment, for they are 

 found not only 

 inside but also 

 outside the blood 

 vessels, showing 

 that they have 

 worked their way 

 between the cells 

 that form the walls 



