I04 Immunity 



and Anderson,* who pursued it with great interest and industry, 

 by Gay,t Gay and Southard, J and others. 



Experimental study shows that when an animal is injected 

 with an alien protein of almost any kind, a reaction takes place 

 that usually is not completed under six days. If a second injec- 

 tion is given before the reaction is peirfected, 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 disturbed biologic equilibrium, the 

 nature of which is not understood, but which is characterized by a 

 profound disturbance that may terminate in death. The reaction 

 is quite specific; the sensitization, once effected, may continue 

 throughout the remainder of the life of the animal and be trans- 

 mitted from the mother to her offspring through her blood. The 

 reaction can be brought about by feeding the protein or by injecting 

 it. It has an important bearing upon infection and immunity, the 

 chief example being seen in the tuberculin reaction. 



The symptomatology of anaphylaxis is interesting and char- 

 acteristic. 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 Mso cc. It is necessary to wait until the effects of this 

 first injection are completely 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 Mo cc, is given. Both 

 doses are given by injection into the peritoneal cavity. 



The symptoms come on almost immediately after the second 

 dose. 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 hour. The 

 disturbances in the body of the animal are sufficient to account for 

 the symptoms. Extensive lesions exist, the first to be described 

 by Rosenau § affecting the mucous membrane of the stomach, which 

 appeared ecchymotic and ulcerated. Gay and Southard |1 found 

 hemorrhages in most of the organs, and believe anaphylaxis to 

 depend upon the presence, in the blood of the sensitized animal, of 

 a substance to which they have given the name anaphylactin. Bes- 

 redka and Steinhardt** found that by the repeated injection of 



* "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," i907,xvi, No. 3, p. 381; "Jour. Infectious Diseases," 

 1907, IV, No. I, p. I, "Jour. Infectious Diseases," 1907, vol. rv, p. 552. 



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



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



§"Bull. No. 32 of the Hygienic Laboratory," Washington, D . C, October, 

 1906. 



II "Jour. Med. Research," July, 1908, xnc. No. i, pp. i, $, 17. 



** "Ann. de I'lnst. Pasteur," February 25, 1907, xxi. No. 2, pp. 117-127. 



