Where can I find this?

On the Marx Brothers Collection
http://www.amazon.com/Brothers-Collection-Casablanca-Service-Circus/dp/B0001HAIP4/sr=8-2/qid=1161090533/ref=pd_bbs_sr_2/002-3560518-5330460?ie=UTF8

In the disk with the picture "Go West", this cartoon is in the Special Features.

Amazon has it in a collection with other Tom & Jerry cartoons.

Warner Brothers Home Entertainment Academy Awards Animation Collection - The 15 Winners
http://www.amazon.com/Brothers-Entertainment-Academy-Animation-Collect ion/dp/B000ZOXDK0/

No two persons ever watch the same movie.