INFECTIOUS GERMS. 259 



tity of substance which produces such extraordi- 

 nary changes. An atom so small that a microscope 

 of the highest power is incapable of defining it, 

 enters the system through the lungs, and passes 

 on into the blood, and from thence into every 

 texture, nerve, and secretion. In a few days the 

 chemical actions of oxidation and nutrition through- 

 out the whole body are completely altered, and 

 the little particle of matter has reproduced itself 

 infinitely. Pustules appear over the whole skin 

 surface, each one loaded with an infinite number 

 of germs identical in nature with the original 

 particle which set in motion the train of dis- 

 organizing forces. There is general peroxidation 

 going on ; there is inflammation of the ears, the 

 eyes, the mucous membranes, the joints, the serous 

 membranes ; everywhere there is great chemical 

 disturbance. This is small-pox, and the terribly 

 disgusting, wretched condition of the bodily func- 

 tions is due to the introduction of a particle so 

 infinitesimally small that no optical instrument 

 can discern, and no balance can weigh it. 



The poisonous .germs producing intermittent 

 fever, or fever and ague, from whatever source 

 they may arise, are probably of a highly complex 

 and nitrogenous nature, and are capable of being 

 dried and carried great distances by the wind. 

 They enter by the mouth with the dust, pass into 



