IO4 Immunity 



by Rosenau and Anderson,* who pursued it with great in- 

 terest and industry, by Gay,| Gay and Southard, J and 

 others. 



The phenomena are those of " hypersensitivity, " or, as 

 now better known, " anaphylaxis." The experimental study 

 shows that when an animal is injected with an alien proteid 

 of almost any kind, a reaction takes place that usually is 

 not completed under six days. If a second injection is 

 given before the reaction is perfected, the mechanism of 

 immunity is set in action, and the animal proceeds to defend 

 itself through the various means described. If the second 

 administration be deferred, however, until the first reaction 

 is completed, it seems to find the animal in a state of dis- 

 turbed biological equilibrium, the nature of which is not 

 understood, but which is characterized by hypersensitiwty 

 or anaphylaxis. The reaction is quite specific; the sen- 

 si tization, once effected, may continue throughout the re- 

 mainder of the life of the animal and be transmitted from 

 the mother to her offspring through her blood. The reaction 

 can be brought about by feeding the proteid or by injecting 

 it. It has an important bearing upon infection and immu- 

 nity, the chief example being seen in the tuberculin reaction. 



The symptomatology of anaphylaxis is interesting and 

 characteristic. When it is desirable to study it, a guinea-pig 

 is first given a sensitizing dose of horse serum. This may 

 be very small. Rosenau and Anderson found one guinea-pig 

 to be sensitized by one 'millionth of a cubic centimeter. In 

 most of their work they used less than -^i^ c.c. It is neces- 

 sary to wait until the effects of this first injection are com- 

 pletely over before giving the poisoning dose. This period 

 of incubation lasts about twelve days. After the lapse of 

 this time, the second dose, usually about TO c.c., is given. 

 Both doses are given by injection into the peritoneal cavity. 



The symptoms come on almost immediately. The 

 animal is profoundly depressed, extremely uneasy, pants 

 for breath, and suffers from intense itching of the face. It 

 soon falls, continues to gasp for breath, and dies within an 



* "Journal of Medical Research," 1906, xv, p. 207; "Bull. No. 29 

 of the Hygienic Laboratory," Washington, D. C., 1906; "Bull. No. 

 36," 1907, Ibid.; "Jour. Med. Research," xvi, No. 3, p. 381; "Jour. 

 Infectious Diseases," iv, No. i, p. i, 1907; "Jour. Infectious Diseases," 

 vol. iv, p. 552, 1907. 



f "Jour. Med. Research," May, 1907, xvi, No. 2, p. 143. 



t Ibid., June, 1908, xvm, No. 3, p. 385. 



