Disney in the late 1930s did animated shorts like no one else did them. Warner Brothers was after the visual gag and creating continuing characters, while MGM was interested in making visually pretty cartoons and mostly one-shots, with few recurring characters. For Walt Disney, shorts served a couple of primary purposes: one, they kept the Disney name and his principal characters before the public and two, most importantly to Disney, they were a good testing and training ground for new animation techniques, so he could make the feature films as close to perfect as possible. In this short (a fantastic cartoon in its own right), the visual gags are great, but the timing on everything has to be perfect or it won't work. You can see the seeds of things Disney did later in features like Dumbo and Bambi in shorts like Mickey's Trailer, which serve as dry-runs while being great works in and of themselves. Some of the best bits ever done were done for these shorts just to see what worked and what didn't. Magnificently animated. Well worth watching. Most highly recommended.