THE INTRACUTANEOUS REACTION 



abdomen or the region of the mammilla, for almost a minute. The diag- 

 nostic value of the reaction is variously interpreted. 



An almost analogous reaction, described independently of Moro, by 

 Lignieres andBerger is to be found in thoroughly rubbing in concentrated 

 old tuberculin into the shaved 

 skin of tuberculous cattle. 



The Intracutaneous Reaction. 



Tuberculin even in very weak 

 dilutions when injected directly 

 into the skin of tuberculous indi- 

 viduals produces marked inflam- 

 matory infiltrates. This was first 

 observed by Mendel and Man- 

 toux and has been carefully 

 studied in cattle and guinea-pigs 

 by Roemer. 



In guinea-pigs the test per- 

 formed is as follows: the hair of the 

 abdomen is removed by calcium 

 hydrosulfid, i/io c.cm. of a 20 per 

 cent, tuberculin solution (0.02 

 c.cm. tuberculin) is injected with 

 a very fine needle directly into the 

 skin. The result is noted after 48 

 hours in order to allow the trau- 

 matic effects to wear off. Roemer and Joseph differentiate three grades 

 of reaction: 



(a) Very susceptible animals (+ + + ) show after 18 to 24 hours a 

 pinkish wheal about the size of a half dollar with a very deep red center. 

 In 48 hours the dark center which represents a blood extravasation attains 

 a greenish hue. After four days a superficial necrosis sets in which leads 

 to sloughing and final scarification. 



(b) In less susceptible animals (++) there is no central dark area of 

 the wheal and the latter appears after 48 hours. These animals show a 

 very slight necrosis later on. 



(c) The mildest form can be differentiated from the traumatic re- 

 action only in that it does not disappear after 48 hours but remains 

 several days. 



In the human being the intracutaneous method has been advised by 

 Hamburger. The results are as yet insufficient to form definite conclusions 

 as to the clinical value of the test. 



FIG. 13. Inoculation with tuberculin for the 

 Pirquet reaction. 



