STUDIES concerning the effects of section of the vagi are numerous and date back to the sixteenth century. In 1883, on the basis of his own experiments and from an extensive review of previous literature, Heidenhain1 emphasized that bilateral vagotomy performed in the neck was inevitably fatal, yet when done below the diaphragm it appeared to be a rather harmless operation. It remained, however, according to Pavlov,2 for Krehl3 in Ludwig's laboratory to evaluate properly the effect of double vagotomy on survival time. He clearly established that animals can survive bilateral section of the vagus below the lung root but invariably succumb after such section in the neck. Later experiments on dogs, cats and rabbits4 and the more recent ones of Ferguson5 on monkeys amply confirmed the results of these investigators. No generally acceptable explanation is, however, as yet available for the fact that this