Evidence has been unearthed that suggests that Mr. Wain was a) pretty crazy throughout his life, and b) not really so much compelled to draw cats in this style as he was trying to parody contemporary art styles, from Expressionism onward. (Apparently, he'd heard he was "sentimental and old-fashioned" once too often...) Coffee mugs with his work are available with The Royal Hospital of St. Bethlehem stamped on the other side.

Sure don't look like owls to me....