INFECTION EXPERIMENTS. 47 



It may be that the organisms of the miasmatic contagions 

 require free oxygen at a certain stage of existence, especially 

 for the hatching of the spores formed in the body, after which 

 the organism itself may enter the body, and multiplying, 

 cause disease. Some examples of this nature have been 

 observed in organisms inhabiting putrid substances. The 

 hatching and early stages of existence take place on the 

 surface, but the after life, the real activity of the organism, 

 is in the depths of the mass, away from free oxygen. Ac- 

 cording to this idea the spores passing out from the sick 

 person must first find a suitable soil for hatching and the 

 beginning of development, before they are ready for growth 

 iii the human body. 



The efforts already made on this theory, for the prevention 

 of the spread of epidemics, have been sufficiently successful 

 to furnish an additional point of circumstantial evidence in 

 favor of its correctness. 



INFECTION EXPERIMENTS. 



Turning again to the experimental evidence, we find that 

 fragmentary experimentation has taken a new departure. 

 Men have arisen from their microscopes and begun injecting 

 the bacterian fluids collected from wounds, and from those 

 dead of disease, into animals, and watching their effects. 

 In the first of these, the animals seemed to have been killed 

 outright by the amount of poisonous material injected, and 

 nothing was gained. 



Cose and Feltz were the first to obtain valuable results. 

 They injected a small quantity of blood from a patient just 

 dead of puerperal fever, into rabbits. The rabbits sickened 

 and died of the disease induced. The blood from these was 

 injected into other rabbits, which also died after a disease of 

 the same nature. This was repeated many times, always 



