Isaac Cathrall: A Medical Sketch of the Synchonus Maligna, or Malignant Contagious Fever as it lately appeared in the City of Philadelphia to which is added, some account of the morbid appearances observed after death, on dissection.” Philadelphia, printed by Thomas Dobson (1794) First edition. In 1794, (Miner 94): Cathrall began experiments on animals that had ingested the black vomit of yellow fever victims, and on himself through subcutaneous injections of blood and vomit. He concluded that this matter is an "inert secretion" of the disease having no morbific power. At the same time, however, Cathrall maintained that yellow fever is contagious: through personal contact, through the medium of air surrounding the victim, and through contact with objects that have absorbed the unspecified contagious matter.
From Catalog I
The clearest case in the collection of a physician reasoning correctly from evidence and reaching the wrong conclusion. Cathrall disproved person-to-person transmission through bodily fluid contact -- which was correct. He concluded the disease must spread through some other mechanism of contact -- also correct. He could not identify what that mechanism was. The mechanism was mosquito bite, entirely outside his experimental framework.
