STUDIES OF SPORE-PLANTS 



perhaps in school where other pupils have shown signs of the 

 disease, and after a number of days, the symptoms of the 

 disease may appear ; examination of the throat discloses 

 certain peculiar spots, and microscopic examination of 

 material from the surface of these spots shows countless 

 thousands of bacteria of the diphtheria species. The reason 

 why the disease did not appear immediately after exposure 

 is that it required time for the one or few bacteria which 

 first lodged in the throat to multiply and form a colony. 



Toxins. Now, the symptoms of diphtheria are not simply 

 those of a sore throat, for the patient is evidently affected in 

 many other organs. This seems surprising, for the bacteria 

 are not so widely distributed ; but the explanation has been 

 found in the fact that the colony of bacteria secrete a poison 

 (toxin) which is absorbed by the blood and then distributed 

 widely in the body. Thus bacteria growing in one organ 

 (local infection) may profoundly affect other organs in the 

 body. 



263. Antitoxins. If the vitality of the patient is strong 

 enough to endure the diphtheria toxin for some days, the 

 climax of the disease is passed and convalescence ensues. 

 The explanation of this conquering of the disease is that the 

 cells of the patient's body have gradually secreted a substance 

 which counteracts the toxin; this is an antitoxin. Those 

 patients whose bodies are not able to secrete enough anti- 

 toxin succumb to the disease. 



Every one who reads newspapers must have learned that 

 doctors now treat diphtheria with an antitoxin obtained 

 from horses. The explanation is as follows. A great many 

 children are not strong enough to make in their tissues anti- 

 toxin sufficient to overcome the poisons of the diphtheria 

 bacteria; and it cannot be known at the beginning of the 

 disease whether the patient is going to be strong enough. 

 Hence, it is desirable to give some artificial aid. No drug 

 has been found to do this. But taking advantage of the fact 



