328 ILLINOIS STATE ACADEMY OF SCIENCE 



reactions are relatively specific but have been observed 

 mostly in experimental animals. 



Vaughan 4 believes that the parenterally administered 

 protein excites the release of specific ferments that are 

 capable of splitting the protean molecule in such a man- 

 ner as to give rise to a toxic product. In a similar man- 

 ner, he contends that the symptoms in the acute stage 

 of the various contagious and infectious diseases are 

 produced, the protein of the various bacterial growths 

 being split by the ferments set free from body cells. The 

 term albuminal he applies to these diseases. The com- 

 paratively few bacteria gaining entrance into the body 

 must multiply, and this is accomplished during the so- 

 called period of incubation. There is no apparent re- 

 sistance during this time on the part of the body cells. 

 The latter must be sensitized before they can begin their 

 combat with the invading organisms and it is not until 

 this actually takes place that active disease symptoms 

 manifest themselves. This theory is dependent on the 

 assumption by Vaughan and Wheeler 5 that the process 

 which results in the production of protein poison causes 

 a splitting of all of the molecules in the material sub- 

 jected to it. This assumption they consider proved by 

 the observation that the non-toxic residues sensi- 

 tize animals against the original protein but not against 

 itself. This opponents claim is fallacious because the 

 amount of protein required to sensitize a guinea-pig is 

 but a minute fraction of that necessary to intoxicate or 

 desensitize the sensitized animal. 



Hyper sensitiveness and Immunity. — Sir Edward Jen- 

 ner observed that the reaction following vaccination after 

 a previous typical vaccinia (cowpox) appeared earlier 

 and ran a shorter course that is the case in typical pri- 

 mary vaccinia. Of recent years this observation has been 

 studied by Von Pirquet, Tieche, Force and others, and 

 the evidence clearly indicates that such an accelerated 

 response to vaccination is an indication of immunity. 

 In case of tuberculin the reaction is also said to be indi- 

 cative of immunity to reinfection. The disappearance 

 of the reaction in a person with a latent lesion, during 

 measles for instance, is not infrequently followed by 



