Give a clear explanation
You gave a source for your third paragraph, but you didn't do so for your second paragraph.  
I'm interested in these two sentences:
"The crafting of a new national identity went with Mexico's hopes for Empire and the emergent nationalism of the period.  The painting is almost pre-Raphaelite in its detail and precision, and has an almost biblical setting or mise-en-scène with a cast of characters."
I have three questions for you:  
What were "Mexico's hope for empire"?  
How is The Discovery of Pulque "almost pre-Raphaelite in its detail and precision"?  
What do you mean that the characters in this painting had a mise-en-scène that was almost biblical?
Write me back.  I want to see that you can tie these statements with what you see in this painting.  Write me on this same string of Blackboard messages.