Alien Menace
Michael O'Malley, Associate Professor of History and Art History, George Mason University
In these cartoons, Irish immigrants are shown as ape-like or as racially different. The cartoon below, for example, makes the contrast explicit. The caption has both the ape and the Irishman proclaiming (in the same accent), that they're glad for the bars between them.

Americans in the mid 1800s were just beginning to consider the theory of evolution. Scientists argued that "facial angle" was a sign of intelligence and character.

When they studied the "physiognomy" or facial structure, or Irishmen, they detected animalistic qualities. James Redfield's 1852 book Comparative physiognomy; or, Resemblances between men and animals saw Irishmen as dog-like.

Redfield mixes claims to science with claims that the Irshman's dog-like character makes him cowardly and cruel.
The cartoon below contrasts Florence Nightingale, the Civil War nurse, with "Bridget McBruiser", the stereotypical Irish woman.

It's important to point out that caricatures of immigrants were common. Germans were stereotyped in beer halls; Chinese immigrants were mocked in caricatures and cartoons; African Americans were almost constantly the subject of demeaning comic stereotypes. The point is not that Irish people suffered more or less than any other group: rather, the remarkable thing is how differently irish people were seen. No one today thinks of Irish people as "not white"or "racially primitive" in some ways, irish people seem sort of "hyper-white."