516 IMMUNOLOGY 



not necessary, tlie areas are frequently covered with small pieces 

 of sterile gauze held in place by adhasive tape. 



The result of the test according to von Pirquet may be a trau- 

 matic, a negative or a positive reaction. The traumatic reaction 

 may appear as an area of hyperemia or the latter may surround 

 a small wheal. These disappear usually within twenty-four hours. 

 There may remain a slight redness and a small crust for a few days. 

 The negative reaction may also resemble the traumatic reaction. 

 According to von Pirquet the redness and swelling should not 

 exceed 5 mm. after twenty-four hours and this should not persist. 



Positive reaction. This begins as a rule after a latent period of 

 several hours. It is characterized by an area of edema (swelling) 

 one or more centimeters in diameter accompanied as a rule by 

 hyperemia (redness). The swelling reaches its height in about 

 forty-eight hours and then begins to subside. The color may be- 

 come darker and even develop a yellowish tinge. The swelling 

 usually disappears within a few days to one week and there re- 

 mains not infrequently an area of pigmentation. 



MoRo's Percutaneous Test. — To use the percutaneous test of 

 Moro one must prepare a salve by triturating equal parts of old 

 tuberculin and lanolin. A piece of this about tlie size of a pea 

 is rubbed for one minute into an area of skin about 5 cm. in 

 diameter over either the pectoral region or the epigastrium. The 

 salve is then allowed to dry for about ten minutes. A positive re- 

 action is indicated by the development of nodules, a rash or of 

 small vesicles in the area tested. The test is not in use at the 

 l)re.sent time. 



Wolff-Eisner Test. — The conjunctival-tuberculin test of Wolff- 

 Eisner is made by instilling one drop of a 1 per cent solution 

 of OT into the conjunctival sac. When positive, the reaction ap- 

 pears as either a simple hyperemia, an enlargement of the follicles 

 or a severe conjunctivitis coming on within sixteen to twenty-four 

 hours. It is no longer regarded as safe for use in testing children 

 because of severe reactions and permanent injury. 



Patch Test. — Pearse, Fried, and Glover (1940) state that the 

 Volmer patch test is as reliable as the Mantoux test. 



Mantoux Ticst. — The intracutaneous test of Mantoux is now 

 regarded by many as the most satisfactory method of determining 

 tuberculin hypersensitiveness. The dosage employed by different 



