.;. . OTHER .REACTIONS 



There is also a local reaction at the site of the lesion, though this 

 is less marked than in tubercle. There is, however, a very 

 marked production of inflammatory oedema at the site of the 

 inoculation, and this furnishes the most certain test for the 

 disease. A hard raised mass is formed, which increases in size 

 for twenty-four hours or more, becoming as large as the palm of 

 the hand, and persists some days. It often gradually travels 

 down the neck (in the horse), as if under the action of gravity. 



It will be noticed that an essential feature in these reactions is 

 the rapid development of symptoms after an inoculation or 

 injection in a subject already infected with the disease. Von 

 Pirquet has brought forward other examples, which, if less 

 dramatic in their course than Koch's phenomenon, are at least 

 comparable with the cuti-reaction. Thus it has been noticed that 

 the second (Jennerian) vaccination, practised some years after the 

 first, runs a rapid course. Von Pirquet has shown that if a 

 revaccination be made a few months after the first, the reaction 

 takes place in twenty-four hours. It does not, of course, 

 develop in the same way as a primary vaccination, but a small 

 papule, often surrounded by an areola, makes its appearance, and 

 lasts some two or three days. 



Chantemesse has observed in typhoid fever phenomena similar 

 to those seen in Calmette's ophthalmo-reaction in tubercle. He 

 instils a single drop of typhoid "toxin" (obtained by cultivating 

 typhoid bacilli in extract of spleen digested with pepsin), and 

 finds that in normal persons there is but a little transient redness, 

 whilst in typhoid patients there is redness, lachrymation, and the 

 formation of a sero-fibrinous exudate. The process attains its 

 maximum in six to twelve hours. He makes use of this reaction 

 as a method of diagnosis. 



The phenomena of the " negative phase," seen probably in all 

 antibodies, but specially studied in connection with the opsonins, 

 are probably similar in nature to these reactions, although the 

 doses of vaccines given are usually so small that the clinical 

 manifestations do not appear. Sometimes, however, this does 

 happen. Thus Irons found that a dose of 500,000,000 dead 

 gonococci caused no reaction in healthy persons ; but if given to 

 patients already suffering from a gonococcal infection, it produced 

 fever, pains in the joints, and general malaise. In most cases the 

 difference between the behaviour of a healthy and infected person 

 or animal is traceable solely in the variations of the opsonic 



