The 1926 BMJ letters page [1] has correspondence discussing what they thought it was. Nothing specifically medical, but something coming up into the throat and quite possibly croup[2]. For a butcher Lights are generally animal lungs, but the 'cure' was taking a small amount of lead shot or mercury to stop the lights rising.

[1] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2523749/pdf/brm...

[2] https://en.wikipedia.org/wiki/Croup which is now tackled with vaccines and modern medicine.