[DAILY DOSE OF DELIGHT #5 (From Yankee Doodle Dandy)]

The clip has lots of references to Americanism. Cohen is wearing a flag in his lapel, the pictures on the stairway remind viewers of past American patriots. People at the parade are cheering for marching soldiers and waving flags enthusiastically. Taking viewers back to 1878 reminds them that being patriot is a long standing American tradition 

 

president Roosevelt commends Cohen for “weRing his patriotism on his sleeve.”

[DAILY DOSE OF DELIGHT #1 (From The Great Ziegfeld)]

Held’s performance is very similar to stage performances prior to this. Her dress is 1890’s style. Her performance is directed at males and her approach is teasing and provocative. 

In addition, the orchestra is visible. 

In later musicals performers sang to each other, not to an audience. 

As you mentioned in your lecture, these musicals were directly influenced by the musicals on Broadway, but in this case, also by vaudeville