352 Chapter XII 



in laboratory animals against the typhoid bacillus and several other 

 bacteria. 



When animals were subjected to different methods of vaccination 

 against toxins, the manifestation of certain phenomena more or less 

 constant was observed ; amongst these must be pointed out especially 

 the rise of temperature, a local reaction and certain modifications in 

 the body fluids. 



Fever is a very general symptom in the course of the vaccination 

 of mammals. A rise of temperature is almost always observed as a 

 result of the injection of toxins. It is very variable, both as regards 

 duration and intensity, and cannot serve as an indicator of the result 

 of the vaccination. In this respect, such great differences have been 

 observed that the attempt to establish any general laws has had to be 

 abandoned. 



Local reaction is also a phenomenon which is very frequently 

 observed during vaccination ; to this von Behring 1 paid great atten- 

 tion. He and his collaborators found that normal horses when 

 [370] injected subcutaneously with small or large doses of tetanus toxin 

 did not present any exudation at the seat of inoculation. The horses 

 which died as the result of a tetanus intoxication and those which 

 got better behaved from this point of view in much the same fashion. 

 In horses, however, which are being vaccinated and which are 

 periodically subjected to gradually increasing doses of toxin, tume- 

 faction at the seat of injection is never absent. Von Behring 

 attributes this difference to the primordial insusceptibility of the 

 living elements which govern exudation in the subcutaneous tissue 

 to tetanus poison. It is only during the process of vaccination that 

 these cells become susceptible and capable of manifesting a visible 

 reaction. I consider that this difference is due more probably to a 

 change in the chemiotaxis of the various elements which contribute 

 to the inflammatory exudation reaction, from a negative to positive 

 type. The cells do not react at the commencement, not because they 

 are not susceptible to the toxin, but rather because their suscepti- 

 bility is too great. During the course of vaccination they become 

 sufficiently adapted to the poison to be able to manifest their normal 

 inflammatory reaction. This explanation certainly harmonises with 

 the fact that during the period of vaccinations in general and of 

 vaccination against toxins in particular, the blood usually presents a 

 more or less distinct hyperleucocytosis. Now, as is well known, this 

 1 " Allgemeine Therapie der Infectionskrankheiten," Berlin u. Wien, 1899, S. 1052. 



