mouse quoted As I Remember Him by Hans Zinsser
For prose, scientific or otherwise, as for riding horses, he believed one should be start sober; when he was writing essays on educational subjects, he felt that a spot of beer put him into the solemn-ass mood and thus a little closer to the state of mind of the professional pedagogue.
— As I Remember Him by Hans Zinsser (Page 291)
my whole life is shaken seeing "-ass" used like this in a book published in 1940