THE STORY OP THE HEART 65 



contraction of the protoplasm, or living matter of 

 which it consists, across the microscopic field (Fig. 19). 

 If it comes in contact with any solid particle, the liv- 

 ing body of the white blood corpuscle will surround 

 and engulf the atom, and in many cases will devour or 

 dispose of it. This action introduces us to the real 

 function of the millions of white blood corpuscles con- 

 tained in the blood of a single person. They may be 

 described as the sanitary police force of the body. It 

 is known that when foreign particles, especially in 

 the shape of germs, gain admittance to the tissues, a 

 rush of white blood corpuscles takes place to the point 

 of infection. They are capable of pushing their way 

 through the thin walls of the finest blood vessels and 

 of thus coming face to face with the enemy that has 

 literally invaded their gates. A battle takes place 

 between the invaders and the defenders, and in many 

 cases, though not in all, the white blood corpuscles by 

 massing together and bringing their serried array well 

 to the front, are able to dispose of disease germs and 

 like particles which otherwise would tend to inflict 

 injury in the shape of disease upon the body. Occa- 

 sionally, however, defeat awaits these wonderful little 

 defenders of the living domain. In the latter case, 

 when defeated, they die, and the frame thus lies at the 

 mercy of the invading microbes. A study of the pro- 

 cess known as inflammation has revealed other curi- 

 ous facts regarding the white blood corpuscles. 

 When inflammation occurs we find in that process, not 

 one of disease as is commonly supposed, but rather 

 an action which represents the body's attempt to de- 

 fend itself against invasion of disease producing germs. 

 The white blood corpuscles or "phagoctyes" as 

 they are also called, issue forth from the minute 

 bloodvessels in large numbers, and the symptoms 



