Toxins and Antitoxins 7 



affinity for certain tissue cells, and this appeared to explain the neuro- 

 toxic character of the symptoms which are observed in tetanus. 



Antitoxins are not formed when any of the chemically defined 

 poisons are introduced into an animal. The effect of toxins is also 

 different from these with respect to the period of incubation which 

 precedes their apparent action in corpore whatever the dose may be, 

 if we except snake venom and eel-serum, where we however have 

 antitoxins formed. According to Ehrlich (1901) toxins enter into 

 specific chemical combination with the protoplasm of certain cell 

 groups, other poisons like alkaloids do not. Substances which enter 

 into chemical combination are assimilable, it being immaterial whether 

 they belong to the class of substances we regard as foods or as toxins. 

 The toxins of vegetable and animal origin possess the same characters 

 as the albumens or their derivatives. Antibodies are formed not only 

 for toxins, but also for food substances, such as milk, serum, etc., which 

 exert no injurious action. 



The food-stuff or toxin enters into combination with the cell or 

 antibody by means of its haptophorous group (see below), and the 

 protoplasm which is capable of combining with these bodies, which 

 in other words, is receptive, possesses corresponding "receptors," which 

 unite with the haptophorous groups. 



Diphtheria antitoxin was found to enter into chemical combination 

 with diphtheria toxin, combining in definite proportions according to 

 what is known as the law of multiples. When a culture-filtrate of the 

 diphtheria bacillus is allowed to stand for some time it is found to lose 

 its toxicity as far as its immediate effects upon experimental animals 

 are concerned. A larger dose of old filtrate is required to kill an 

 animal in 24 48 hours than when a fresh filtrate is used. Neverthe- 

 less the filtrate continues to combine with antitoxin in the same 

 manner as before. In other words, the combining power remains, the 

 toxic power is lowered. This is due to the conversion of toxin into 

 " toxoid." Ehrlich concluded from the above observation that the 

 toxin-molecule contains two independent atom-complexes, the one 

 haptophorous (which persists), which combines with the antitoxin or 

 the corresponding cell receptors, the other toxophorous (labile), being 

 the cause of the specific toxic effect. The haptophorous group serves 

 as an intermediary in binding the toxophorous group to the cell. 



When an animal is treated with culture-filtrate containing toxoid 

 it is rendered immune to toxin, and its serum is found to contain 

 antitoxin. According to Ehrlich, the haptophorous (non-toxic) group, 



