TUBERCULIN REACTION 



597 



The usual or normal reaction begins to appear in from four to six 

 hours, reaches its maximum intensity in from twenty-four to forty- 

 eight hours, and then fades rapidly, although the infiltration may persist 

 for some days. Special types of the reaction have been described as 

 follows: 



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FIG. 122. METHOD OF PERFORMING A VON PIRQUET TUBERCULIN TEST. 



The abrasion is being made over the insertion of the deltoid muscle. The 

 borer is held firmly and perpendicular to the arm. A quick rotatory motion serves 

 to remove a circular area of epidermis. 



The borer is shown in the upper right-hand corner. 



1. The premature reaction, characterized by a rapid course and slight 

 intensity. This type is supposed to occur in patients with manifest 

 tuberculosis who are not doing well. 



2. The persisting reaction, which reaches its maximum intensity 

 about the second day and persists for a week or longer. 



