270 An Introduction to Medical Mycology 



in an identical direction. At a point on the right side of the hack at a 

 symmetrically selected area, an injection is then made for control. 



2. INTERPRETATION 



The interpretation depends on the development of skin changes at the 

 test site. The reaction is rarely as pronounced as in direct testing. It also 

 evolves more slowly. The degree of reaction is determined by comparison 

 with the control. The test site or sites should be observed after 10 minutes 

 (for an immediate wheal reaction); after 48 hours and one week the pres- 

 ence of a delayed (tuberculin-type) response has not been reported. A 

 positive reaction demonstrates the presence of sensitizing antibodies (re- 

 agins) circulating in the patient's blood. A negative reaction does not 

 necessarily mean that the patient is not sensitive to the test substance. 



BIBLIOGRAPHY 

 Vaughn, W. T.: Practice of Allergy (St. Louis: C. V. Mosby Company, 1939), p. 195. 



