I2& ESSENTIALS OF BACTERIOLOGY 



Roux and Yersin, in 1888, discovered that the injection of the 

 filtered culture bouillon (that is, freed of all diphtheria bacilli) 

 gave rise to the same palsies as when the bacilli themselves were 

 introduced. 



Toxins of Diphtheria. The toxins may be separated from 

 three-weeks-old bouillon cultures by nitration. They are not 

 albumins and are very complex. Ehrlich claims two principles: 

 one he calls toxone. The other, toxin, the toxone produces para- 

 lytic symptoms, and appears to be less affected by antitoxin. 

 The toxins are highly poisonous o.ooi c.c. may be sufficient 

 to kill a guinea-pig in less than twenty-four hours. The sub- 

 stance is unstable, losing its toxic power gradually. Heating 

 at 58 C. for two hours is destructive, but drying renders it 

 more stable. 



Antitoxin. Behring found that animals rendered immune 

 had a principle in their blood that was antagonistic to the 

 development of the toxin. 



Immunity. Brieger and Frankel, by injecting 10 to 20 c.c. 

 of a three-weeks-old culture of diphtheria bacilli, which had 

 been heated at 70 C. for one hour, produced an immunity in 

 guinea-pigs against the virulent form. 



The strength commonly employed in human beings is 3000 

 units, and as much as 20,000 units may be given without detri- 

 ment in severe cases. If this amount is injected into a child 

 suffering from diphtheria in the earlier stages (second to third 

 day), the disease is often arrested. The membrane begins 

 to disappear, and in two or three days has vanished. The con- 

 stitutional symptoms are likewise greatly influenced by the 

 injection. For prophylaxis and immunizing well persons 

 1000 to 1500 units are employed. 



In such conditions as asthma severe and fatal results have 

 followed the use of the serum. 



The antitoxin has no influence on the bacteria themselves; 

 their virulence and length of residence in the body are not less- 

 ened. 



The toxin generated by the germ is supposed to be neutralized 

 by the antitoxin and prevented from injuring the body tissues. 



