508 THE WONDER OF LIFE 



ing sometimes between the two sexes), there is also a 

 typical specific chemical constitution which cannot be 

 widely departed from if the species is to persist. The 

 muscle extract of a modern man pulled the anaphylactic 

 trigger in the guinea-pig which had been treated a month 

 before with extract of mummified muscle. We know in 

 other connections that there is a demonstrable specific differ- 

 ence between the blood of a horse and the blood of an ass. 

 There is a specific chemical constitution which is on the 

 whole the best for the species in question, being stamped 

 with survival-merit after thousands of disadvantageous 

 aberrations have been sifted away through thousands of 

 years. Thus we come back from anaphylaxis to what was 

 said of old : ' All flesh is not the same flesh : but there is 

 one kind of flesh of men, another flesh of beasts, another of 

 fishes, and another of birds '. We are here close to the 

 idea of a chemical definition of a species, which will not 

 be other than complementary to a psychological one. And 

 it is here that Professor Bichet makes a notable contribution, 

 pointing out the specific or racial value of this curious pro- 

 perty of anaphylaxis. 



' I am more and more convinced ', he writes, ' that every 

 detail of the organism has a protective role, and is useful 

 and even necessary to life, and that, therefore, a great 

 general biological function like anaphylaxis must play 

 an essential part in the defence of organisms. So that 

 anaphylaxis appears to us an efficacious and energetic 

 method of maintaining the chemical stability of our bodies 

 by provoking an immediate and violent reactional response 

 to the introduction of any substance which might change 

 it. This is not the defence of the individual ; it is the 

 defence of the species at the cost of the individual '. 



