Second, I can duplicate the DNA with some time in my lab and isolate the antigen, meaning I can make someone immune to our enemies' powers.
The molecules which lead to the production of anti-substances are usually known as antigens, and each antigen has a specific combining affinity for its corresponding anti-substance, fitting it as a lock does a key.
In the first group, the anti-substance simply combines with the antigen, without, so far as we know, producing any change in it.
In the second group, the anti-substance, in addition to combining with the antigen, produces some recognizable physical change in it; the precipitins and agglutinins may be mentioned as examples.
In the third group, the anti-substance, after it has combined with the antigen, leads to the union of a third body called complement (alexine or cytase of French writers), which is present in normal serum.