570 ANAPHYLAXIS 



profession was shocked to learn of the sudden death of the healthy child 

 of an eminent German professor following a prophylactic injection of the 

 serum. In 1902 von Pirquet began the study of these clinical mani- 

 festations with a child in Escherich's clinic who, after receiving a second 

 dose of horse serum ten days after the first, on the same day developed 

 symptoms of fever and a rash. On the basis of this observation von 

 Pirquet 1 reached the conclusion that the prevailing views regarding the 

 length of the incubation period of an infectious disease could not be 

 correct. He therefore propounded the theory that the organism con- 

 cerned in the etiology of disease calls forth symptoms only when it has 

 been altered by antibodies, the period of incubation representing the 

 interval necessary for the formation of these antibodies. 



In conjunction with Schick, von Pirquet endeavored to study all 

 infectious diseases from the same point of view, especially smallpox, 

 measles, recurrent fever, streptococcus infections, and the reactions to 

 cowpox virus, tuberculin, and mallein. Later these same observers 2 

 studied the symptoms following injection and reinjection of horse serum, 

 designating the train of symptoms "serum sickness." They empha- 

 sized that a single injection of serum may suffice to bring about the 

 symptoms, and that this immediate reactivity possesses diagnostic 

 value in so far as it enables us to decide whether a previous infection 

 has occurred. How near the astute Jenner came to reaching the same 

 conclusion is shown in the following abstract from his report in 1798: 



" It is remarkable that variolous matter, when the system is disposed 

 to reject it, should excite inflammation on the part to which it is applied 

 more speedily than when it produces the smallpox. Indeed, it becomes 

 almost a criterion by which we can determine whether the infection will be 

 received or not (italics ours). It seems as if a change, which endures 

 through life, had been produced in the action, or disposition to action, in 

 the vessels of the skin; and it is remarkable, too, that whether this 

 change has been effected by the smallpox or the cowpox, that the dispo- 

 sition to sudden cuticular inflammation is the same on the application 

 of variolous matter." 



Von Pirquet at this time proposed the term "allergy," from ergeia, 

 reactivity, and allos, altered, meaning altered energy or a changed re- 

 activity, as a clinical conception expressing a truth without binding 



1 Zur Theorie der Infectionskrankheiten (Vorlaufige Mitteilung), April 2, 1903. 

 "Zur Theorie der Vaksination, " Verhandl. d. Gesellsch. f. Kinderh., Kassel, 1903. 



2 Wien. klin. Wochenschr., 1903, xvi, 758, 1244; 1905, xviii, 531. Die Serum- 

 krankheit, Leipsic, Deuticke, 1905; Munch, med. Wochenschr., 1906, liii, 66. For 

 a full bibliography on this subject of allergy up to 1910 see von Pirquet, Archiv. Int. 

 Med., 1911, vii, 259 and 383. 



