MANUFACTURE OF ANTI-TOXINS 71 



The first two have proven of more definite value than the rest. 



Manufacture of Anti-toxins. If small doses of a given poison, 

 such as diphtheria toxin, be repeatedly injected into a susceptible 

 animal, and if the dose is gradually increased, there appears, after 

 a time, in the blood serum, an anti-body, or anti-toxin. This 

 substance in the serum is secreted by the cells and corresponds to 

 the free receptors in Ehrlich's lateral-chain theory. If an animal 

 be injected with the anti- toxin, and then with a large dose of toxin 

 say ten times the amount necessary to kill it if it had not 

 received the anti-toxin it will not be harmed. Here the free 

 receptors artifically supplied to the animal unite with the hapto- 

 phorous chains in the toxin molecule, and naturalize, or bind, the 

 toxophorous or poisonous chains in the molecule, and prevent 

 toxophore from attacking important vital cells belonging to the 

 animal. And if the anti- toxin and toxin, after being mixed in a 

 test-tube, are injected into a susceptible animal, no harm results, 

 if they are in proper proportions, since the same thing has hap- 

 pened in vitro that happened in the animal, the receptors and 

 haptophores have united; the toxophores are bound, and the 

 animal is unharmed. 



The manner of making the diphtheria anti-toxin can be taken 

 as a type. 



Diphtheria bacilli are grown for seven to ten days in . i percent 

 dextrose bouillon at 37C.; as the bacilli grow they elaborate a 

 very powerful poison or toxin, which is highly complex in composi- 

 tion. Strains that habitually grow on the surface of the bouillon 

 are used, the access of air enhancing the production of toxin. It 

 is easily decomposed by heat, light and oxygen, and should be 

 used soon after it is prepared. After the cultures have grown for 

 several days, the bouillon is filtered through a porcelain filter, and 

 is then stored in sterile bottles in an ice chest. Horses are gen- 

 erally immunized, since they are susceptible to the action of the 

 toxin, and are easily managed. Before being used they are care- 

 fully tested with tuberculin for tuberculosis and with mallein for 



