Abstract.The electrical responses of taste fibres in the chorda tympani of Macacus rhesus were recorded during the application of various sapid substances to the tongue. Integrated responses from the whole nerve indicate that this monkey possesses taste fibres responding both to the four conventional classes of taste substances NaCl, acid, quinine and sugar, and also positively to pure water. Records from few‐fibre and single‐fibre preparations showed that each fibre has a specific pattern of sensitivity to the various sapid substances. Certain gustatory fibres responded very specifically to one class of substances only e. g. to salt, acid or to quinine. Fibres responding to sucrose almost always responded to saccharine as well, sometimes also to water, and occasionally to other sapid substances which do not taste sweet to humans, such as quinine or acid. The monkey seems to be the first animal investigated possessing taste fibres responding to sucrose which also respond to saccharine. The least specific taste fibres in this animal seem to be those responding to water.