XV 



SPECIFIC BACTERIAL REACTIONS 



ALLERGIC PHENOMENA— TUBERCULIN TESTS— LUETIN, 



GONORRHCEAL AND TYPHOID TESTS— SCHICK'S 



DIPHTHERIA TOXIN SKIN REACTION 



The interesting subject of hypersusceptibility, 

 anaphylaxis or aWeTgy has been sufficiently reviewed 

 in Chapter TV. It will be recalled that allergy is 

 merely an incident in the process of immunization and 

 signifies simply the reactive changes exhibited by an 

 individual after infection or the injection of some 

 foreign sustance or antigen. Allergic phenomena, 

 therefore, may be characterized as those associated 

 with increased sensitiveness ( anaphylaxis ) , and those 

 with diminished susceptibility (prophylaxis). It is 

 apparent that a number of skin manifestations as 

 erythematous and urticarial eruptions of serum sick- 

 ness, exanthemata of eruptive fevers, " disposition to 

 sudden cuticular inflammation " noted by Jenner in 

 his studies of cow-pox in 1798, tuberculin reactions, 

 etc., are pure allergic phenomena, since they are the 

 exponents of localized foreign proteins and the toxic 

 substances incident to their destruction by the specific 

 antibodies in the blood of the sensitized body. Con- 

 spicuous among the allergic reactions to which practi- 

 cal consideration at this time will be given are the 



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