Lassie - Episode 106 - "Graduation" - Season 4, #3 (9/22/1957)

Jeff accepts a summer job as animal vet Dr. Weaver's assistant. While Dr. Weaver is on a call, Jeff asks Timmy to hold down the office when he has to run out for a moment. Timmy takes the time to play at being a vet, but then accidentally lets a sick dog loose on the street.
TRIVIA: There were 11 children in Jeff's grade school graduation, and he was the Valedictorian. The term is an Anglicized derivation of the Latin vale dicere ("to say farewell") which foreshadowed what Tommy Rettig ("Jeff Miller") was doing in real life in regards to the Lassie series. Jon Provost (Little Timmy) had already taken over much of the episode's scenes, including being with Lassie in the opening credits, and in only 10 more episodes Rettig (Jeff) would be saying farewell to the series for good.
NOTE: This recording has been edited to remove commercials and to add titles and descriptions. The re-broadcast has not been stretched or modified in any way from the original film which was distributed for TV viewing in classic black and white early 1950's "square TV screen" format. "Lassie" is copyrighted and owned by Classic Media. The first 4 seasons of "Lassie" were later syndicated as "Jeff's Collie". Recorded from COZI TV in 2013 via free over-the-air antenna TV.