Ferris et al. 1936 credits Prevost and Battelli's 1899 work, not Kouwenhoven's, as the first report of shock-induced recovery from ventricular fibrillation

Immediately before presenting its own 60%-recovery counter-shock result in sheep, the paper states its own priority explicitly: "Recovery of the heart from ventricular fibrillation by the application of a short intense shock was reported first by Prevost and Battelli in 1899. Kouwenhoven, Langworthy and Hooker also have reported the recovery of dogs from fibrillation by the application of what has recently been termed a 'counter-shock.'"

This bears directly on the vault's existing account of the electrocution-safety → defibrillator lineage, which traces the defibrillator back to William Kouwenhoven's 1920s Consolidated Edison–Johns Hopkins program. Ferris et al. 1936 shows that Kouwenhoven's dog-recovery counter-shock work was already published and known by 1936 — the two programs are contemporaries citing each other, not strictly sequential — and that both ultimately trace the underlying phenomenon to a single earlier demonstration: Prevost and Battelli, 1899, thirty-seven years before this paper and roughly two decades before Kouwenhoven's program began. The exact citation (journal, year) for the Kouwenhoven, Langworthy and Hooker paper referenced here was not chased down this session and remains a loose end for tightening this timeline further.