Poor lad — broken a thumb at such a young age, then made to get all dressed up for family. He does appear to have a brace (the black in his palm), which would indicate a pretty serious break, and the lack of our ultra-modern materials means it looks a lot worse than if you broke it today. These days, we have flesh-colored or transparent high-strength tape and carbon-fiber braces that make it all but invisible. In the thirties, they had cloth tape — or that might even be a plaster cast. Also, remember this farm was probably a good 5 to 10 miles from the nearest town…if they went to a doctor at all. If a neighbor or even dad was handy with medical supplies, the only doctor consulted was a copy of the Modern Home Medical Advisor that came free with $10 of groceries down at the Red Owl.
