THE LAWS OF PROTOPLASM 1 33 



found when the symptoms of these germ diseases 

 are present. Man alone is subject to about one 

 hundred such diseases, while the number affecting 

 plants and animals as a whole must be many 

 thousands. In each one of the diseases caused by 

 specific organisms there are equally specific 

 symptoms each of which requires definite treat- 

 ment. This is the reason why patent medicines 

 misrepresent their claims. Each patent medicine 

 might be helpful to a single disease but it is utterly 

 impossible to conceive how it can have any re- 

 medial influence for the many diseases usually 

 specified. 



When science established the fact that definite 

 organisms were associated with specific diseases, 

 one of the greatest discoveries In medicine was 

 made. Since this point of view has been the domi- 

 nant one notable progress has been possible. But 

 the mere presence of these organisms does not ex- 

 plain how they cause disease nor how an organism 

 recovers. Neither of these problems is satisfac- 

 torily solved in all biological diseases, although 

 great progress has been made, but we can illus- 

 trate In some cases how disease is caused. 



The poisonous rattlesnakes are well known to 

 cause death as a result of biting man and animals. 

 In the head of the rattlesnake is found a large 

 salivary gland which is now devoted to the pro- 



