The Immigration and Nationality Act has been amended
many times. When Congress enacts a law, it generally does not
re-write the entire body of law, or even entire sections of a
law, but instead adds to or changes specific words within a section.
These changes are then reflected within the larger body of law.
The language changing the larger body of law is generally referred
to as the "amendatory" language. Here you will find
laws "amending" both the INA
(Immigration and Nationality Act) and the U.S.
Code.
Link to the Public
Laws Amending the INA.