SERUM DIAGNOSIS 117 



stances great enough to draw blood. A small tuft of 

 cotton is applied to each drop to prevent its flowing 

 away. The center scarification serves the purpose of 

 a control with which to compare the spots to which 

 the tuberculin is applied. 



The reaction is considered positive when the tuber- 

 culin spots give a hyperemic zone of 4 to 6 mm. with 

 a papule in the center. From such a feeble reaction the 

 reaction may vary in intensity to the production of 

 numerous papules with considerable edema and redness, 

 persisting for several hours. 



Ophthalmo-reaction, Wolff-Eisner and Calmette Test. 

 A drop of dilute tuberculin is instilled in the eye. A 

 positive reaction is characterized by congestion of the 

 palpebral conjunctiva and caruncle, with more or less 

 serofibrinous exudate. The reaction disappears in 

 from twenty-four to forty-eight hours. 



The Moro Reaction. This is a cutaneous reaction 

 produced by applying a tuberculin ointment to the un- 

 broken skin. 



A concentrated ointment of tuberculin in anhydrous 

 lanolin is used, and a small amount energetically rubbed 

 into the skin of the abdomen or breast for about a minute. 



A positive reaction is characterized by the appearance 

 in from a few to twenty-four or forty-eight hours of a 

 granular or papular eruption of varying intensity, ac- 

 companied by more or less itching, and lasting from a few 

 hours to several days. Of these several local tests, the 



