362 INFECTION AND RESISTANCE 



toxin contents of the injected serum, but could be produced (though 

 somewhat less markedly) with horse serum alone. He also showed 

 that, while a preliminary injection of horse serum "sensitized" a 

 guinea pig to a subsequent dose given after an interval of 10 to 12 

 days, the repeated injection of considerable quantities at short inter- 

 vals produced a condition of "antianaphylaxis" or immunity to the 

 later injections. Otto, too, excluded from his results the direct rela- 

 tion of the anaphylactic state with the possible presence of serum 

 precipitins, a thought suggested by Morgenroth in his interpretation 

 of the observations of Magendie mentioned above. 



Eosenau and Anderson 10 had attacked the problem with the pri- 

 mary purpose of throwing light upon the occasional accident of sud- 

 den death following the injection of diphtheria antitoxin into human 

 beings. Since the detailed description of their extensive investiga- 

 tions would tend to render more difficult the exposition of an already 

 sufficiently complicated subject, it will be best to tabulate the chief 

 results of this classical series of their earlier papers. Briefly, these 

 are as follows : 



1. A single injection of horse serum into guinea pigs, harmless 

 in itself, renders these animals hypersusceptible to a subsequent 

 injection given after a definite interval or incubation time. 



2. This interval, with the ordinary dosages employed (about 1 

 to 2 c. c.), was about 10 days. Properly carried out injections after 

 this period were usually fatal. 



3. The known antibodies, antitoxins, hemolysins, and precipi- 

 tins, are not responsible for the reaction. 



4. The reaction is "quantitatively" specific, injections of horse 

 serum sensitizing to horse serum only. (The question of specificity 

 will be further discussed below.) 



5. The sensitive condition is transmissible from mother to off- 

 spring, 11 the young of sensitized mothers being hypersusceptible to 

 a first injection of horse serum. 



6. The reaction is extremely delicate. Rosenau and Anderson 

 succeeded in sensitizing in one case with 0.000001 c. c. (one one- 

 millionth) of horse serum. 



7. The hypersusceptible state is not a transient condition, but 

 may last a long time. 



8. Sensitization, or the production of the hypersusceptible con- 

 dition, can be carried out, not only with the various animal and vege- 

 table proteins employed in the first experiment, but can be brought 



10 Rosenau and Anderson. U. S. Pub. Health and M. H. S. Hyg. Lab. 

 Bull 29, 1906; 30, 1906; 36, 1907; Journ. Med. Ees., Vol. 15, 1906, Vol. 16, 

 1907; also Jour. Inf. Dis., Vol. 4, 1907, Vol. 5, 1908. 



11 It is important practically, as Anderson points out, that a female 

 guinea pig may transmit to its young sensitiveness to horse serum and im- 

 munity to diphtheria toxin. 



