What did the Immigration Act of 1924 do?

During my research of basic information of the Visas and what is an alien, I found out many new things about getting a Visa and how much effort is put in to get one.  Although the year was in 1924, the regulations were very strict.  Even leaving the states and coming back was regulated by people checking boat docks to make sure everyone coming in to the states is legal.  There were also many exceptions to leaving the states and coming back, many were regulations to make sure that any citizen that leaves, is still a citizen when they come back if they meet certain requirements i.e. work for the government.  There were also many people who could not get in because they did not meet all of the requirements to become a citizen of the US of A; which in turn made many people upset.  Not only that regulation, but there could only be a certain amount of visas the could be given out to people, so it was also a competition against their friends of who could earn the visa.  Aliens were also talked about as people who are coming in to the States from a different country.  They were not allowed in unless they had a visa, but learning about what makes a person be considered as an alien was