506 THE WONDER OF LIFE 



interest, since they are the people known to us all, to whom 

 ' eggs are poison ', who cannot digest milk in any form, 

 or who cannot eat a particular kind of shellfish without 

 more or less serious symptoms, such as nettlerash and 

 fever. Instances are known of people becoming very 

 seriously ill through having unconsciously partaken of some 

 disguised form of the substance to which they have such 

 a violent constitutional antipathy. A scientific light is 

 thrown on the adage, ' what is one man's food is another 

 man's poison '. In this connection, again, the phenomenon 

 of anaphylaxis is absolutely specific, and Dr. Bichet cites 

 the case of a man who always showed violent symptoms 

 after eating even a perfectly fresh shrimp, yet who could 

 indulge freely in lobster without inconvenience. He 

 strained at a gnat, but could swallow a camel with ease. 



Another complexity is what is called ' passive anaphy- 

 laxis '. That is to say, if the blood of an animal which 

 has been anaphylactized in regard to a particular sub- 

 stance be injected into another animal, that also becomes 

 anaphylactic to the same substance. A little seems to 

 go a long way in producing a remarkable change. Inter- 

 esting also is the fact that anaphylaxis in a mother, acquired 

 either before or after conception, may be acquired by her 

 offspring, so that they are born anaphylactic. Diffusion 

 of a substance from the mother's blood to the offspring's 

 must have occurred during the ante-natal life. But the 

 condition of congenital anaphylaxis is not of long duration. 

 In guinea-pigs it was noted on the forty-fourth day, but 

 had disappeared by the seventieth. 



Professor Kichet's theory of anaphylaxis, that is of the 

 precise way in which the condition is brought about, is 

 too technical for our present purpose. Suffice it to say 



