In 1947/48 season, Jack finally reached the age of 39. Before that, he had been 38 for awhile, and the running gag was that anywhere he went, someone would eventually ask his age; particularly at the doctor's office. "Weight, height, eyes...oh, they're blue aren't they?...age - 38...pause....more questions....age....38." As Jack left the office, the nurse asked again...age? 38.
Anyway, when he reached the 47/48 season, he finally allowed himself to be 39 and never left it.