Recent work on the growth of wool in relation to the cystine supply in the sheep's diet, together with the discovery in proteins of a new sulphur-containing amino acid, methionine, has directed attention to the importance of being able to determine, by methods easily and quickly carried out, the amounts of total and inorganic sulphur in plant products and feeding stuffs. Details are given in the present note of the methods employed by the writers for the estimation of total sulphur, sulphate sulphur and, by difference, organic sulphur.