The Internal Secretion of Protease by the Salivary Gland of the Larva of the Blowfly Calliphora erythrocephala

high correlation (r 0.89); the corresponding value for the colorimetric method was r 0.70. A highly significant correlation (r -0.97) between pyruvate (P,) and the olfactory threshold concentration of onion juice has been observed by Schwimmer & Guadagni (1962). The importance of thiolsulphinate as an unstable intermediate in the production of the components of onion that contribute to its flavour and odour is clear.