Combined electron and light microscopy in Whipple's disease. Demonstration of "bacillary bodies" in the intestine.

Order of authorship in the original publication: Yardley, Hendrix. The authors made the first observations of previously uncultured, unseen and unidentified bacilli associated with Whipple's disease, suggesting that it was caused by an infection. 

(Thanks to Juan Weiss for this reference and its interpretation.)