an obsolete test of patency of the fallopian tubes; a cannula is introduced into the cervix uteri, and carbon dioxide gas is passed through the cannula by means of a syringe with manometer attachment; if the tubes are patent, the escape of gas into the abdominal cavity is evidenced by a high-pitched bubbling sound heard on auscultation over the lower abdomen, or free gas under the diaphragm can be demonstrated by radiograph.