The effects of the modified Heller's esophagomyotomy on function of the lower esophageal sphincter in the dog were studied. In normal dogs, this surgical procedure produced a les competent lower esophageal sphincter that still maintained the ability to prevent esophageal reflux.

Gastrografin (diatrizoate meglumine and diatrizoate sodium solution) was used to evaluate its performance as a gastrointestinal‐tract contrast medium in ten cats. It was administered through an orogastric tube to ketamine hydrochloridesedated, nonatropinized, mature cats at a dose rate of 22 mg/kg. Gastric emptying and largeintestinal filling were observed within 30–60 minutes in seven cats and in 120 minutes in the remaining three cats. The mucosal detail of the small intestine was poor, being represented by a homogeneous “halo” of decreased radiodensity surrounding the more radiodense intestinal luminal contents. The contrast medium refluxed into the esophagus in six cats. Some contrast medium precipitated in the stomach and small intestines in all ten cats. Urinary‐tract opacification occurred in all cats and was first seen 60 minutes after Gastrografin was administered. Gastrografin satisfactorily opacifies the lumen of the gastrointestinal tract of cats. It has physical and physiologic characteristics that preclude its use for routine gastrointestinal contrast studies. These characteristics are reviewed in this article.