RED AND COLORLESS CORPUSCLES 



163 



Man 



Frog 



Red corpuscle of a man compared with that of 

 a frog. 



lives ; and it carries food to the body cells. In the cells work is 

 performed, oxidation takes place, and heat is released as energy. 

 The almost constant temperature of the body is also due to the 

 blood, which brings to the surface of the body the excess heat 

 given off by the oxidation of food in the muscles and other tissues. 

 The Red Blood Corpuscle, its Structure and Functions. — The 

 red corpuscle in the blood of the frog is a true cell of disk-hke form, 

 containing a nucleus ; while 

 that of man is in the form 

 of a biconcave disk, without 

 a nucleus. So small and so 

 numerous are these corpus- 

 cles that about five million 

 of them are found in a 

 cubic millimeter of nor- 

 mal blood. Their color, a 

 dirty yellow when separate 



corpuscles are viewed under the microscope, is due to an iron- 

 protein combination called hcemoglo'hin. Haemoglobin will combine 

 chemically with oxygen, forming a bright red compound called 

 oxyhcemoglohin. In the parts of the body where oxidation is 

 going on, the red corpuscle releases its load of oxygen and takes 

 ap in exchange carbon dioxide. This results in a change of color 

 to dull red. Thus the red corpuscles are gas carriers. 



The Colorless Corpuscle, Structure and Functions. — The color- 

 less corpuscles, of which several kinds are found in the blood, are 



irregular in outline, as 

 they constantly change 



^ , ^^ , I — . their form. The color- 



Lymphocyte Polynudedr /eucocyrej , , , 



'^ 1^ ^ ^ less corpuscles are less 



Two kinds of colorless corpuscles. numerous than the red, 



the ratio being about 1 to 700 in a normal person. They greatly 

 increase in number in certain diseases. They have the power of 

 movement, 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 of the blood tubes. 



A Russian zoologist, Metch'nikoff, after studying a number of 

 simple animals, such as medusae and sponges, found that in such 



