Susceptibility of Protozoa to Poison. 83 



the less strength and also were more susceptible to the influence 

 of copper sulphate. 



46 (302) 



The relative specificity of anaphylaxis. 

 By F. P. GAY and E. E. SOUTHARD. 



[From the Pathological Laboratory of the Harvard Medical School. ] 



The anaphylaxis in guinea-pigs caused by the previous injec- 

 tion of any one of the protein substances, horse serum, egg white, 

 or milk is only relatively specific. The maximum reaction on 

 second injection is always obtained when the substance which has 

 sensitized is used, but in certain combinations intoxication can be 

 produced by the other two substances. This intoxication, by a 

 heterologous protein is " partial " and does not occur if the " com- 

 plete" intoxication, produced by the homologous protein, has 

 been effected ; when " partial " intoxication has been produced by 

 one or both of the heterologous substances, "complete" intoxi- 

 cation may still be effected by the homologous substance. The 

 intensity of an homologous intoxication, after anaphylaxis by a 

 single substance, would seem to vary somewhat with the substance 

 used, the order of toxicity ranging, egg white, serum and last of 

 all milk. After combined anaphylaxis, produced by initial injec- 

 tion of all three substances, the first intoxication, allowing of 

 course a proper incubation period, may be produced by any one 

 of the substances in question. When intoxications are effected 

 with each substance in turn the serial set of symptoms varies ac- 

 cording to the order in which the substances are injected on the 

 subsequent days. When injected as the second or third of the 

 series, egg white alone produces maximal symptoms at all times ; 

 horse serum is diminished in toxicity if used after either egg or 

 milk and loses markedly if used after injection with both sub- 

 stances. Milk is very slightly toxic if given second in order and 

 absolutely non-toxic if given third ; this would compare with the 

 actual toxic power of each substance as noted after homologous 

 sensitization. The mixed anaphylaxis then is only relatively spe- 

 cific, since egg and horse serum will completely preempt the pos- 

 sibility of intoxication by milk if this substance is given last. 



