238 MICROBES AND TOXINS 



pulmonary alveoli or the skin. We are here in a region as yet 

 little explored; there are many mysteries in the action of drugs, 

 there are still greater mysteries in the experimental study of 

 diseases of nutrition. Once again anaphylaxis raises this 

 general problem of nutrition, towards which already the whole 

 study of immunity is directed, and it is probable that, did we 

 know more of this, we would be less ignorant of the nature of 

 life, old age, and death. 



Let us consider then separately what knowledge has been 

 gained on the subject of anaphylaxis to those substances which 

 have been most studied, the poisons and serum. 



Researches on the Poisons. — There have been studied 

 by Richet the congestin of Actinians, the congestin extracted 

 from mussels, and a vegetable toxin, analogous to abrin and 

 ricin (well-known from Ehrlich's experiments), called crepitin, 

 and extracted from the plant Hura crepitans of the Euphor- 

 biacese, known in Brazil under the name of Assaku. The 

 mytilocongestin (from mussels) produces vomiting, a symptom 

 very definite and easy to observe, a great convenience in 

 experimental work. " The symptoms of anaphylaxis to 

 crepitin are exactly the same as with actino- or mytilo-con- 

 gestin, and even the most acute observer, I am sure, could not 

 distinguish them. . . . There is the same profound abolition 

 of all innervation, both motor and sensory, and above all, 

 vaso-constrictory : there is the same intense haemorrhagic 

 congestion of the intestine with an enormous fall in the 

 arterial pressure " (Richet). 



It is to be observed that these belong to the group of slow 

 poisons — resembling thus the bacterial toxins— which differ 

 from the crystalloid group such as strychnine, and it is probable 

 that on this depends their anaphylactic effect. 



An animal is rendered anaphylactic because the first 

 injection has induced in it, after a period of incubation, the 

 formation of a new substance, an antibody, the product of a 

 reaction of the body. This antibody is not itself poisonous, 

 but it liberates a poison when it comes in contact with the 

 congestin or crepitin of the second injection. 



