Although first discovered in a horse by Eustachius,1 a Roman anatomist in 1565, in dogs and other species by Asellius1 in 1622, and in man by Veslingius2 in 1634, the thoracic duct may be said to have yielded as a surgical organ a decade ago, when this structure was first successfully ligated by Lampson3 for the treatment of chylothorax. Peet and Campbell,4 in 1943, had ligated the thoracic duct for chylothorax, but their patient succumbed suddenly following the ligation, the cause of death being undetermined. In the era prior to Lampson's successful ligation the thoracic duct was shrouded with mystery. Not only was the impunity with which the thoracic duct can be ligated unrecognized but, in addition, ligation was strongly forbidden.5-7 The collected cases of traumatic chylothorax are listed in the accompanying Table. Since Lampson's successful ligation, thoracic-duct ligation for the treatment of chylothorax