Vaccination. 



Koch's 

 Circuit. 



BACTEMOLOGY IN A NUTSHELL. 



The antitoxin treatment is somewhat similar 

 in its effects to vaccination as a protection 

 against small-pox. The theory has been ad- 

 vanced that vaccination against diphtheria and 

 other communicable diseases may come to be 

 an established method during epidemics. 



It is claimed by Koch that in order to prove 

 that a certain germ or micro-organism is the 

 cause of a specific disease it must produce cer- 

 tain effects. Briefly, these are as follows : 



I. — Where the disease is present there the 

 specified germ must always be found. 



II. — The germ found in the diseased body 

 must again grow and multiply in proper culture 

 media outside of the body. 



III. — The same disease must be reproduced 

 in a healthy animal by using the poison or 

 toxin obtained from the culture media in which 

 the germ has multiplied. 



IV. — The same germ must again be found in 

 the serum of the blood of the animal thus in- 

 oculated as a result of the process. 



Koch further states that it must be proven 

 that no other germ is capable of producing the 

 disease under consideration and that if the 

 original micro-organism is not found all 

 through the process the suspected disease does 

 not exist. 



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