Excerpt from "Neighbor, How Long Has It been ?  The Story of Wolf Brand Chili, A Texas Legend" by Wallace O. Chariton

...... Soon after its inception, the legend of the can car took a dramatic and unexpected turn. One day, West was out on a sales call in the wolf truck and his young son, Jimmy, the boy that had once had custody of Kaiser Bill, was along for the ride.  To entertain himself on the trip, Jimmy pulled out his harmonica and struck up a simple tune.  As soon as he started playing, Kaiser Bill started howling.
Alarmed, Jimmy stopped playing. West was intrigued and told Jimmy to play some more. He did and Kaiser Bill chimed right in.  A few more tests produced the same results and a new dimension was added  to the already successful promotion - wolf howling on demand.  Whenever the truck and Kaiser Bill were on display, the crowd could be serenaded with authentic wolf howls simply by blowing a few notes on a harmonica.
Surprising enough, the company never had problems with Kaiser Bill in the cage, other than a few unfortunate times when he chose an inappropriate moment to hike his leg.  Although people were allowed to get close the the truck for a better look, Bill never bit anyone and rarely growled. Some people who still remember seeing the wolf are positive that he liked all the attention.  ....

Probably the first photograph ever taken of the original
Wolf Brand Chili Can car, as it was called.  The cage on the back
was for Kaiser Bill and later replaced with a stuffed wolf.  The little
girl is is Bonnie Ruth Slauson, Fred Slauson's daughter.

Kaisar Bill in the original Can Car

This photo was taken in the 1930s in front of a Dallas Grocery Store, the cage was replaced by a display case with a stuffed wolf.

Notes:

• See Also: Wolves Went With Chili Salesmen