farmers' institutes. 253 



in our laboratories that most of our disease g-erms can be increased or 

 decreased at will in their poisoning properties, their virulence. Thus 

 suppose I decrease the poisoning- powers of the blackleg germ, and now 

 inject it into a calf, the calf does not die but recovers because the germ 

 could not secrete enough strong poison to kill it. Now, however, if the 

 calf becomes infected with the virulent germ of blackleg after it has re- 

 covered from the milder one, it will not now die, because its system has 

 built up something to destroy the poison of the milder germ. In doing 

 this, however, the system of the calf has fortified itself so that when the 

 more virulent germ attacks it, it can now successfully cope with the more 

 virulent poison and does not sicken at all. There are many ways in which 

 we can decrease the virulence of a germ and then use it for vaccination. 



You all know what is known as smallpox vaccine is now obtained 

 from cows. Formerly we obtained it from the arms of human beings. 

 According to the best experimental evidence thus far obtained cowpox 

 is smallpox of the human being modified in virulence by being- passed 

 through the cow. It was formerly traced to a disease among horses 

 known as "grease." Therefore, cowpox is smallpox made mild by 

 passing it through the cow. Now the vesicles from the belly of a cow 

 which is inoculated with cowpox yields our vaccine. The sterilized ivory 

 points are dipped into the matter scooped from the vesicles of a cow with 

 cow-pox, or it is mixed with glycerine and sealed up in little glass tubes. 



Now. when one is vaccinated his arm is inoculated with cowpox 

 or modified smallpox. The disease is so mild that one has only a slightly 

 sore arm. As in the case of the calf with the blackleg vaccine, so in the 

 case of the human being after being vaccinated. His system in resisting 

 the mild poison of the vaccine has so fortified itself that it can now fight 

 the real virulent smallpox when exposed. Something has been produced 

 in his system which neutralizes or destroys the poisons of smallpox. 

 This fortifying substance built up in the body as a result of vaccination 

 may last only a few months or it may last a life time. One cannot tell. 

 The only safe rule is to be vaccinated every time one is exposed to small- 

 pox. Even twenty-four hours after exposure to smallpox vaccination 

 will save one from the disease. When vaccination is localized on the skin 

 the immunity is produced so rapidly that the poison of smallpox is over- 

 come before it can be generated in sufficient quantity to cause smallpox. 



The sore arm is caused by uncleanliness. If the proper care is taken 

 by the doctor and patient during and after the vaccination there should 

 be no sore arm. The sore arm is due to an infection. If all of our 

 people were properly vaccinated there would be no smallpox. 



