444 SANITATION 



not only white corpuscles and germicides, which kill the 

 germs themselves, but also substances that neutralize 

 the effect of the toxins. These are the antitoxins. For 

 every toxin that germs produce, the body probably forms 

 an antitoxin. In diphtheria the patient may not be able 

 to produce enough antitoxin to stop the disease, but if he 

 is helped by the addition of some diphtheria antitoxin to 

 his blood, he may win his fight against the germs. Like- 

 wise, if one who has been exposed to the disease is treated 

 with antitoxin, the germs may not be able to develop 

 enough of the toxin to cause the disease. 



The diphtheria antitoxin is produced in the body of the horse. The 

 method is as follows: 



Germs taken from some one who has the disease are allowed to 

 multiply in a rich nutrient like beef broth. They thus produce a great 

 deal of the toxin. The germs are then filtered out, and the liquid 

 containing the toxin is injected under the skin of a horse. The horse's 

 blood produces antitoxin to neutralize the toxin. As more and more 

 toxin is injected, more and more antitoxin is produced. The horse 

 becomes immune to, or " fortified against," the toxin. Then blood is 

 drawn from the horse, and is clotted and filtered. The resulting 

 filtered liquid is the antitoxin serum. When some of this is introduced, 

 under the skin, into the human body, it makes the body immune, or 

 at any rate helps in making it immune, to the toxin produced by the 

 diphtheria germ. 



The records of many hospitals show that while before the days of 

 antitoxin there used to be 30 to 50 deaths out of every 100 cases of 

 diphtheria, the deaths since the introduction of antitoxin are only 

 from 11 to 18 in 100 cases. If the antitoxin is pure, and if it is used as 

 soon as the disease shows itself, there are practically no deaths. 



434. Smallpox. Typhoid, tuberculosis, and diph- 

 theria are germ diseases, but they are not accompanied by 



