234 MICROBES AND TOXINS 



This chapter of experimental medicine was opened up by 

 the experiments of Richet and Portier on the poison of 

 Actinians (1902). 



Anaphylaxis to Poisons— Richet's Experiments. — 

 From the tentacles of actinians a poison may be extracted 

 which has been called congestin, because it produces in the 

 animals injected an intense congestion of the viscera, of the 

 stomach, liver, kidney, and, above all, the intestine. The 

 fatal phenomena do not appear until after several hours of 

 incubation. If a dog which has recovered from a small dose is 

 inoculated after a certain interval of time with -^-^ of the 

 quantity of the first dose, violent symptoms suddenly appear 

 after a few seconds, severe vomiting, difiScult respiration, 

 paralysis, profuse and blood-stained diarrhoea. On comparing 

 the size of the dose with its effect, it works out that the 

 dog has become, between the first injection and the second, 

 eighty times more susceptible. 



Anaphylaxis to Normal Serum — Arthus' Phe- 

 nomenon. — If a rabbit is injected subcutaneously every six 

 days with 5 c.c. of horse serum, it is found that after the fifth 

 injection the serum is absorbed with difiSculty ; succeeding 

 injections produce local lesions which continually increase in 

 severity, from simple inflammation to actual necrosis of the 

 tissue. The same phenomenon may be produced with milk 

 instead of serum. 



" Serum-sickness " : Observations of Von Pirquet 

 and Schick. — Therapeutic sera (antidiphtheria, antitetanus) 

 are almost always got from immunized horses ; they are not 

 invariably devoid of toxicity for man. In a small proportion 

 of cases, about 14 per 100, the injection is followed by various 

 symptoms, not very severe it is true, which only appear after 

 an incubation period of five to fifteen days, and consist of 

 urticaria, erythemas, and pains in the joints. But should the 

 patient fall ill again months or years later, long after the serum 

 has disappeared from his body, and should he be reinjected 

 with it, the symptoms are reproduced and are more frequent 

 (86 per 100, according to Weil-Halle and Lemaire), more 



