Assay of gastrin by means of its gastric acid stimulating activity.

1. A method is described for the bio-assay of gastrin activity in the anaesthetized cat, based on the acid stimulating activity of gastrin.2. A ;gastrin' of unknown potency can be assayed in terms of a stable Standard Gastrin Extract or of Synthetic Human Gastrin I.3. The sensitivity of the method is such that it will detect quantities of Synthetic Human Gastrin I at least as small as those at present described as detectable by radioimmunological techniques.4. The precision of the assay is such that it falls in the category that has been described as very precise and well suited to clinical studies.