ANAPHYLAXIS. 383 



The poison was invariably fatal for dogs when 

 given as a first injection in doses of 0.8 gm. per 

 kilogram of animal weight, but was rarely fatal 

 in doses of under 0.2 gm. per kilogram. Death 

 usually occurred in from four to nine days. When 

 a second dose, however, was given to an animal 

 which had recovered from the first injection, 

 death supervened in a short time, usually within 

 two and three-quarters hours. The first injection 

 evidently modified the resistance of the animal in 

 some way so that it became more susceptible to 

 the poison than it was in the first instance. It 

 was to this modified state of the animal's resist- 

 ance that Eichet applied the name "anaphylaxis," 

 which stands in contrast to a condition of pro- 

 phylaxis. 



In 1903, Arthus observed that, when rabbits 

 had received several injections of horse serum at 

 intervals of several days, the serum ceased to be 

 absorbed as at first and that there resulted local 

 necrosis and often sloughing with subsequent ulcer 

 formation. 



In 1904, Theobald Smith told Ehrlich of a Theobald 

 phenomenon which he had observed while testing Phenomenon. 

 the potency of diphtheria antitoxin on guinea- 

 pigs. Animals which had received injections of 

 antitoxic horse serum and later were injected with 

 a small quantity of normal horse serum became 

 acutely ill or died. 



In the following year, 1905, appeared the ar- 

 ticles of Otto, Eosenau and Anderson, and of v. 

 Pirquet and Schick. Since these articles an 

 enormous amount of work has been done to cor- 



