Disease and Immunity 93 



tion only in part. As a consequence, heat is 

 called the degraded form of energy, and is al- 

 ways a product of work performed. When a 



person takes violent exercise, as in a foot race 

 or a wrestling match, his temperature increases 

 and may rise to 105° F., or more, and such ap- 

 pearance of extra heat is evidence of the exer- 

 tion he makes. A fever represents an increase 

 in the heat form of energy and is evidence of a 

 physical struggle of some kind which is invisible 

 because it is within the body. The invisible 

 struggle which produces a fever is said to be 

 disease, and the visible struggle of a foot race 

 which correspondingly raises temperature is not 

 disease. Is a question of disease to turn upon 

 the degrees of visibility? Is a bacterium to be 

 considered as the cause of disease because he 

 can be seen only with a microscope, and an oppo- 

 nent in a wrestling match not the cause of disease 

 because he can be seen with the naked eye? 



Resistance to disease consists of power to 

 fight off whatever it is that causes disease. All 

 persons are more or less resistant to diseases of 

 all kinds. If they were not, then they would die 

 the instant a disease touched them. Even in case 



