CONTROL OF DISEASE 347 



ARTIFICIAL IMMUNITY IN CONTROL OF DISEASE 



1. Susceptibility variations 



Kinds 



Individual variations 

 Family variations 

 Racial variations 



Specific variations (that is, differences between species of 

 animals) 

 Probable reasons 



Chemical differences in blood 

 Chemical differences in metabolism 

 The reaction products of protoplasm 

 The by-products of metabolism 

 Differences in other behavior of protoplasm 

 Possibly physical differences in cell walls etc. 



2. Immunity 



Natural 



Inherited chemical qualities of blood etc. 

 Inherited reaction habits of white corpuscles 

 Inherited reaction habits of protoplasm 

 Acquired 

 Passive 



Use of drugs (for example, quinine) 

 Use of antitoxin 

 Use of other aids to resistance 

 Active 



Recovery from specific disease 

 Vaccination or inoculation 

 Living parasites 

 Non-living parasites 

 Toxin 

 Broken 



Malnutrition 



Exhaustion 



Fatigue 



Chilling 



Poor circulation 



Effects of previous sickness 



Constipation 



Worry and nervous strain 



