How did immigration to america change in the latter half of the nineteenth century, and what was the response to that change?

Immigration in the late 19th century in the US was the highest immigration numbers of all time. As nationalist movements in Europe pushed people out, the fast growing industrialization pulled people into the US. Immigrants began coming from Eastern and Southern Europe for the first time bringing many Catholics, Jews, and even Muslims in addition to many languages and cultures not known in the US. These groups created ethnic communities in cities where their language and culture could continue. Americans reacted in one of two ways: nativism or reform. 
The nativists claimed to be the "native" Americans focused on racial issues and white "native" Americans being the rightly members of the United States. 
Reformers worked to assimilate immigrants into society providing education, jobs, and cultural training. The most famous of which was the Hull House in Chicago run by Jane Addams. 

Assemblies do not have written codes of laws. laws are matters for magistrates and courts, not assemblies. codes of law are things such as civil law, criminal law, and constitutional law. what assemblies have are procedures regarding debating, voting and other business they might carry out.  also note that rome had three assemblies: the assembly of the soldiers, the assembly of the tribes, and the plebeian councils.