TOXIC OR EXCITING INJECTION 37 



The toxicity of egg-albumen disappears after it has 

 been heated even without coagulation. Its behaviour 

 in this respect is the same as that of blood-sera; 

 whilst the dose of 0-002 c.c. of egg-albumen is suffi- 

 cient to determine fatal anaphylactic shock, a dose 

 of o-i c.c. or even of 0-3 c.c. of this same solution, 

 heated to 100° C, is tolerated by the sensitised animal 

 without any ill-effects. 



Does an animal sensitised with the white of the hen's 

 egg react anaphylactically if the test injection is made 

 with the white of egg of another species of bird — 

 say, for example, the pigeon or the turtle-dove ? In 

 other words, is the toxic function of the egg-albumen 

 specific ? 



The result of our experiments goes to shew that 

 the toxicity is specific for a given species, but that this 

 specificity is not absolute. Thus, a guinea-pig sensitised 

 with the white of the hen's egg tolerates as much as 

 o- 1 c.c. of the white of the pigeon's or turtle-dove's egg, 

 but if the dose of this latter be raised ever so little 

 (0-5 c.c), the most characteristic anaphylactic symp- 

 toms are immediately produced. The egg-albumen 

 of alien species therefore only becomes toxic as the 

 doses are raised; egg anaphylaxis then possesses a 

 relative specificity. 



In speaking of the action of heat on the toxicitj'^ of 

 egg-albumen we have said that the latter is thermo- 

 labile — that is to say, that the heated solution appears 

 to be deprived of toxicity. We should remark, how- 

 ever, that this loss of toxicity is only quite relative. 

 It is in evidence when it is administered to guinea- 

 pigs that have been sensitised with raw egg-albumen, 

 but if the test be carried out in animals that have 

 been sensitised with the heated egg-albumen, one is 

 quite astonished to discover — and we have repeated 

 this experiment a number of times — that intravenous 

 injection made with /tea/ec? egg-albumen ranks amongst 



