From this I think that the cause of croup is simply the result of abnormality of the cerumen system.
"Philosophy of Osteopathy"
Andrew T. Still
A question arises-and stands without an answer-is this substance which is commonly called ear-wax, technically called cerumen, is it dead or is it alive while in this form and visible?
"Philosophy of Osteopathy"
Andrew T. Still
A term applied to the glands secreting cerumen, or ear wax.
"A Practical Physiology"
Albert F. Blaisdell